I modifed an Excel colorimeter spreadsheet for use with the SpyderTV originally posted by forum member garyfritz in the thread "Colorimeter Help?". This is designed to be used with the SpyderTV '/support' option and the black through 100IRE grey window patterns in 'Avia: Guide to Home Theater'. The spreadsheet will plot gamma curve (total, r, g, b), and color temperature.
==========================================================
Update: 12, Nov 2005
- Added macro button for importing colorimeter xyY data from Derek Smith's S2xyY utility. This button is labeled "S2xyY". You will need to enable macros to use this.
- Added Avia correction factors. You can select whether you want to use these from the drop down field in box K3.
- Changed the "Relative RGB Levels" graph so the user can select what reference color they want to use by selecting from the drop down field in box K6.

Update: 31, Oct 2005
- Added sheet for calibrating primary and secondary colors (red, green, blue, cyan, magenta, and yellow)

Update: 26, Oct 2005
- Added a *.ods version of the file to support OpenOffice 2.0 Calc
- Added a tab to support GetGrey's calibration DVD

Update: 25, Oct 2005
- Changed calibration instructions to use Avia Window patterns instead of grey fields.
- Luminance curve is now normalized to account for black level resulting in consistant gamma regardless of brightness setting.
- Color space conversions (XYZ->RGB) now use rec 709 matrix.
- Gamma curve and gamma calculation based on rec 709 idealized monitor transfer function.
- Displays calculated gamma for red, green, and blue curves
- Updated documentation and calibration procedure

Update: 5, Oct, 2005
-Added instructions on first sheet.
-Changed Relative RGB Levels graph to display error relative to ideal RGB value
-Use calculation from BruceLindbloom.com for calculating gamma for a dataset. Excel solver is no longer necessary to estimate Gamma.

Update: 17, Jan, 2006
- Added tab for Digital Video Essentials
- Added color sheet for PAL
- Added color sheet for NTSC
- The color decoder sheets do not show up right in Open Office and I have no idea how to fix this. Hopefully someone can help me out.


Right click save-as to download the zip file with the excel spreadsheet. Please PM me if you cannot download the file and I will email you a copy.

Tried on 3 different computers - no luck downloading the file.

It downloaded and opened, OK on my PC.
Using MS XP Pro and Mozilla.

I would not use this spreadsheet in its current form for the following reasons.

The spreadsheets RGB calculations are not very useful for calibration to D65. The RGB error displayed in this spreadsheet decreases to zero at 100 IRE no matter what the color measurement is. What you want to see is the color error in relative RGB levels at each IRE level to D65 not to the measured 100 IRE value as found in the spreadsheet.

This spreadsheet references only color temperature not D65.

Assuming zero light level at zero signal input to normalize the gamma curve is flawed.

The input signal level is assuming Avia levels for test patterns. This will be incorrect for many other test sources.

I also have other issues with these calculations, but they are less serious.

Gary's spreadsheet was one to which I referred in the STV review. As Jeff says, it has several errors, some of greater and lesser significance.


Later,
Bill

The spreadsheets RGB calculations are not very useful for calibration to D65. The RGB error displayed in this spreadsheet decreases to zero at 100 IRE no matter what the color measurement is. What you want to see is the color error in relative RGB levels at each IRE level to D65 not to the measured 100 IRE value as found in the spreadsheet.

Thanks for pointing that out. I was just adjusting using gamma and xyY values and never paid much attention to the "Relative RGB Fields". I changed it in the latest version to show error from the ideal RGB values (based on x=.3127 y=.329).


This spreadsheet references only color temperature not D65.

This may sound like a dumb question but what is the difference?


Assuming zero light level at zero signal input to normalize the gamma curve is flawed.

Well, I cannot get the Spyder TV to take measurements on my set below 20IRE, so even if the spreadsheet took into account light level at 0 input level I do not understand what use it would be. I don't really understand this feedback because we are normalizing based on the 100IRE level.


The input signal level is assuming Avia levels for test patterns. This will be incorrect for many other test sources.

Yep. :) I might do a seperate sheet for DVE, but for now this is just for Avia.
Hopefully the update I posted will correct the major flaws. I appreciate your feedback.

...This may sound like a dumb question but what is the difference?
..

D65 is a specific color while correlated color temperature is a line in xy colorspace. You must calibrate to D65 for gray scale to achieve the desired results. This link shows these lines. http://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-org/chap18/F18-05%20CCT%20in%20xy%20diagram.jpg

...Well, I cannot get the Spyder TV to take measurements on my set below 20IRE, so even if the spreadsheet took into account light level at 0 input level I do not understand what use it would be. I don't really understand this feedback because we are normalizing based on the 100IRE level...

Your display must have very low black levels. This is also one of the problems with using Avia. The difference between the 7.5 and 10 IRE patterns is not very large. However, all displays will not have levels so low that the SpyderTV cannot measure them. You are in a bind though if it can't.

The problem with the calculation method in this spreadsheet will show up with displays that have higher black levels. Your normalized Y values (P55-P64) are wrong because of this. You are dividing by the maximum value, but you should also subtract the minimum value because your ideal curve is always starting at zero. All displays are not capable of zero black levels and many are fairly high. The error in your calculated gamma will increase with black level.

Here are examples based on simply modifying the spreadsheet to include a variable black level. This is simulated by adding a constant to the measured Y values. The calculated gamma should not change because of a shift in light level up in your form of gamma calculation. Black levels up to 0.4 cd/m2 are not uncommon. Here are the results.

Black Level (cd/m2) Calculated Gamma

0.00 2.33
0.05 2.11
0.10 2.01
0.15 1.95
0.20 1.90
0.30 1.82
0.40 1.77

There are other problems with the gamma calculation because it is not the Rec. 709 equation. The real gamma compensation being used in the majority of displays today is including the linear section found in the specification for gamma compensation. Here is a link to more information on this. Without this linear segment you will be calculating that the gamma compensation is much lower than it really is.

http://people.ee.ethz.ch/~buc/brechbuehler/mirror/color/GammaFAQ.html#RTFToC5

Gary's spreadsheet was one to which I referred in the STV review. As Jeff says, it has several errors, some of greater and lesser significance.

Bill, I noted in that thread that you have your own spreadsheet that (from the sound of it) is quite comprehensive. If that's true is it available for use?

Bill, I noted in that thread that you have your own spreadsheet that (from the sound of it) is quite comprehensive. If that's true is it available for use?
Tony - it will be soon. However, I'll have a dedicated thread for it when it's released.

I finally got a chance to update this and take another stab at getting my RPTV calibrated. I posted the updated version at the top of the thread.
Thanks Jeff (umr) for taking the time to point out the errors and providing such a concise and easy to understand explanation. You get my vote for forum MVP!

thanks rader,

for updating it. I was going to calibrate my pj tonight.

I read somewhere that the AVIA IRE greyscale is a little bit off and DVE is better. I have both. should I use DVE instead, even thought the patterns is only in 20IRE steps.

I am also curious as to why you changed to using the windowed pattern.

Thanks again for the spreadsheet

Thanks for the vote rader. It just turns my stomach to see people using calculations that are so flawed. Your calculations look reasonable now.

I would make one more change so Avia or non-Avia gray windows can be used with the spreadsheet. To do this you need to add a variable for 0 or 7.5 IRE black level patterns and calculate the normalized input level with either 100 or 92.5 as the range and 0 or 7.5 as the offset. This is not dependent on what the player outputs, but the percentage level of the pattern itself.

I would also consider adding a color tolerancing function. Delta E 1976 is the most commonly used. You would need to add Lab color calculations to do this. The following is a link to this calculation. To use it so it is color only you need to reference each measurement to the actual measured L value. This will result in L being 100 for each value.

http://www.brucelindbloom.com/index.html?Eqn_DeltaE_CIE76.html

thanks rader,

for updating it. I was going to calibrate my pj tonight.

I read somewhere that the AVIA IRE greyscale is a little bit off and DVE is better. I have both. should I use DVE instead, even thought the patterns is only in 20IRE steps.


What I do is use the Avia Window patterns and the spreadsheet to set the gamma curves so they are as close as possible, and then switch to the DVE window patterns to fine tune greyscale. It would probably be a good idea to add some instructions on how I do this to the spreadsheet.
If I knew the greyscale error in Avia I might be able to add a compensation into the spreadsheet.


I am also curious as to why you changed to using the windowed pattern.


Two reasons:
1. The Windowed patterns in Avia start off with a black window field which needs to be measured in order to properly calculate gamma (see Jeff's (umr) post above showing how the flawed gamma calculation varies with black level).
2. On CRT based diplays full field patterns at the high IRE levels will cause clipping and make it impossible to set greyscale/gamma unless contrast is reduced to a very low level. I think Guy Kuo says something about this in the forum FAQ thread posted by ChrisWiggles at the top of this forum.

Jeff (umr),
Wow, thanks again. Looks like I have some more homework to do!
Sorry for turning your stomach earlier. :)

...Jeff (umr),
Wow, thanks again. Looks like I have some more homework to do!
Sorry for turning your stomach earlier. :)

No problem, you were just following what others had done before. I am just glad to see that you have something very useful now.

You will need to add more complexity to your calculated curves and gamma if you make the change to include Avia and non-Avia test patterns.

I have posted some correction factors for Avia on my web site. These measurements are based on the gray scale step pattern and show the significance of the errors at low input levels.

http://accucal.org/documents/Avia_Correction_Factors.doc

will this also work with the Spyder2Pro, I have one on order so I can cal all my screens including 2 dlp projectors

thanks for putting this together

another suggestion is to also support the calibration disk by GetGray being developed http://www.avsforum.com/avs-vb/showthread.php?t=586139&page=1&pp=30

These bundled would make a great low cost cal system

...another suggestion is to also support the calibration disk by GetGray being developed http://www.avsforum.com/avs-vb/showthread.php?t=586139&page=1&pp=30

These bundled would make a great low cost cal system

That is what I am suggesting with altering the black level point.

Great is overstating the accuracy of the Spyder. I would rate it as the beginning of a good low cost calibration system. You need to add an optical comparator to your equipment list to touchup the color errors that the Spyder will likely induce in your display to have a system that is adequate.

Jeff - Here you rag on your PVM-96:
http://www.avsforum.com/avs-vb/showthread.php?p=6373309

...which lists for $900. Given how frequently you post telling people to add an optical comparator to the Spyder, this seems somewhat inconsistent. If one is too cynical, it might even be somewhat disingenuous given your software interest.

Later,
Bill

Jeff - Here you rag on your PVM-96:
http://www.avsforum.com/avs-vb/showthread.php?p=6373309

...which lists for $900. Given how frequently you post telling people to add an optical comparator to the Spyder, this seems somewhat inconsistent. If one is too cynical, it might even be somewhat disingenuous given your software interest.

Later,
Bill

It is not inconsistent at all.

My PVM-96 or any other comparator I have used are not perfect but it is frequently much more accurate than my filter based colorimeters. I recommend a spectroradiometer if you want the most accurate color measurements. What I am saying is if you are targeting something that has a reasonable chance of being good then you should try and use a comparator to touch up the colors.

People here seem to want advice on how to come relatively close at minimal expense. I am offering what I believe would be the best approach for most people with the Spyder if they want to do a decent job. There are other simpler techniques that I and others on this forum have described before that can work as well at approximating D65 that are much less expensive, but those will not work on all displays.

Personally, I just want people to have decent colors and using a filter based instrument alone is not likely to give it. I can't do anything about your cynisim. Most people are buying software other than mine and I only started selling it because you and Ken asked me to. I never intended to offer it for sale to the general public. I could discontinue selling it if that would make you feel better.

Bill,

The following quote captures more of my thoughts on the issue of inexpensive gray scale calibration tools.

http://www.avsforum.com/avs-vb/showthread.php?p=6007324&&#post6007324

I would rate the options in order of cost and quality in the under $1k category to obtain a good color calibration as follows.

I would only consider a spectroradiometer or an optical comparator if you want accurate colors for anything, but a CRT. This is based on several less than stellar experiences with filter based colorimeters. I cannot begin to tell you how satisfying it is to pay over $1k for a colorimeter that tells you a screen is blue when it is red. If you can adjust the color gamut on your display then an optical comparator is not sufficient.

1. Purchase a Kodak gray card as a D65 reference and a good 6500K light source like this http://www.hellolights.com/150wat65iw.html . This is the lowest cost option and not likely to yield poor results assuming you know how to adjust the cuts and drives to get it right.

2. Hire an ISF calibrator who has a good optical comparator, spectroradiometer, signal generator and test media that fit your sources including possibly DVD, D-VHS and LD. Do not underestimate the importance of quality test equipment and skill.

3. Buy a new Sony PVM-96 D65 monitor and use it as an optical comparator. This is a better optical comparator option and not likely to yield poor results assuming you know how to adjust the cuts and drives to get it right.

4. My software with an Eye-One Pro spectroradiometer for an instrument with excellent accuracy assuming you are unwilling to hire this capability.

You could always sell the Sony PVM-96 or the Eye-One Pro when you are done to reduce the cost if you choose one of those options. You can probably recover more of you cost for the Eye-One Pro than the PVM-96.

will this also work with the Spyder2Pro, I have one on order so I can cal all my screens including 2 dlp projectors

Sure, just select tools->colorimeter from the Spyder2Pro menu. You can use this to get xyY measurements from whatever display you are using. If you have an HTPC hooked to your DLP you can also use the Spyder2 calibration tools.
----
I posted a new update with an additional sheet tab for GetGrey's calibration disk. I adjusted the levels to the best of my understanding from umr's description. I do not have a copy of the disk so I can not test these changes. If someone who has GetGrey's disk could test it out that would be great.
I also included an OpenOffice 2.0 version of the spreadsheet so you do not need to buy Excel. I do not know how to use OpenOffice so the chart formatting could use some work. If anyone knows OpenOffice Calc well I would appreciate some help cleaning up the charts.
I also took a stab at the Delta E 1976 calculation and graph. Have not tested it yet so there is about a 99.9% probability it has some error(s). It is on the "GetGrey" sheet if anyone wants to take a look. I should have it functional for the next revision.
---

I have posted some correction factors for Avia on my web site.

umr, is there any question you don't have the answer for? :) I will see if I can implement the corrections in the spreadsheet. Thanks again!

....
I also took a stab at the Delta E 1976 calculation and graph. Have not tested it yet so there is about a 99.9% probability it has some error(s). It is on the "GetGrey" sheet if anyone wants to take a look. I should have it functional for the next revision.
---

umr, is there any question you don't have the answer for? :) I will see if I can implement the corrections in the spreadsheet. Thanks again!

Your Delta E calculations look correct to me. You should round them to whole numbers. Additional precision is not realistic. The graph should not have negative values for Delta E since it can only be positive.

I don't know the answer to many questions, but I have pondered many of the ones you have asked.

Bill,

The following quote captures more of my thoughts on the issue of inexpensive gray scale calibration tools.

http://www.avsforum.com/avs-vb/showthread.php?p=6007324&&#post6007324

Jeff - This does represent more thought-out advice, especially with the acknowledgment that the filter-based tools have differential accuracy between CRTs and lamp-based displays. However, what I was responding to are the far more common posts from you that do not offer such a nuanced opinion. I respect that you have issues with the filter-based colorimeters, but to state this opinion as an authority as frequently as you do without the background information seems counter to your stated purpose (e.g., several CRT owners thinking that the Spyder is not good enough for them).

What I have never seen you respond to is how to have confidence in the EyeOne at high and low light levels. Per your statements, it can get x and y right compared to a Lightspex. In my own limited testing, Y has been suspect at best at the high and low ends (e.g., readings of 1.2 cd/m^2 in one run, then 0.2 in another -- which matches what my Spyder returns consistently). As you know, x and y are merely transforms of XYZ, so getting x and y correct without getting X and Y right is a violation of basic algebra - unless they are off in exactly the right proportions to one another to make the aggregate ratios perfect (unlikely).

You had chided me previously for using averages in my own testing protocols, but that is in fact what you should do in cases like this. You should also look at standard deviations and standard errors across multiple testing runs. To do otherwise is incorrect. Please note: yes, I believe that the EyeOne is a better meter (it costs twice as much before taking into account your software, so it better be!). However, I have yet to see a good comparison of the Spyder against reference grade equipment. So, could you either a) be more complete in posting your advice, or b) participate in a valid colorimeter shoot-out? The point being not to prove that one is good and the other must stink, but to show where the relative strengths and weaknesses are.

As for your software, if you read my posts (search using the term "Jeff's software" with my userid), you will see that I have been very positive in recommending your software. I think it is a good thing for the market.

Later,
Bill

Bill,

I have seen and appreciate your support.

I am completely into statistics as well. I am not saying taking averages or calculating population statistics is worthless. I was quibbling with a statement that implied using an average value guaranteed accuracy. All it is likely to do is increase repeatability. My software actually uses some statistics and averages behind the scenes in a more complex manner than simply averaging xyY values.

The Y reported by the Eye-One is different than the XYZ coordinate system. The xy and Y values are calculated from the SPD of the radiometric measurements. I have not seen the variance you are describing seeing at 1 cd/m2 on the Eye-One.

I have done my own shoot out with my SpyderTV versus my Eye-One. You are welcome to come to my house and see how it performs on the variety of displays that I have (CRT direct view, LCD direct view. LCD RPTV, LCoS RPTV). I am not saying the SpyderTV stinks completely. I am just trying to add some balance to peoples excitement about these instruments.

Here is my take on the SpyderTV based on my own experiments...

It is a useful light meter, but no more sensitive than the Eye-One. The diffuser mounted on it makes it unreliable for luminance measurements. This means it cannot measure screen gain and is less useful for calibrating an RPTV's light levels. It is not calibrated for illumination, but since it has a good diffuser it should take measurements that are relatively linear, but the units will be in error. Therefore, it cannot be used to calculate a projectors lumens.

As a colorimeter it is a mixed bag. On some of my displays it is very accurate on others it is over 0.01 in x or y off. It seems to do well on LCD direct view and CRT direct view sets. It seems to be less reliable on other technologies. As long as its use is limited to those display types my experience with it is good. Other display types are more problematic. Filter based devices also tend to be hygroscopic causing the calibration to drift after several months.

I also find the SpyderTV to be slow and cumbersome to use.

I just think people should understand the caveats of what they are purchasing. The reason I was posting on this thread was to help correct some of the errors people were likely to make using the spreadsheet. I was only suggesting using an optical comparator because that is what I would do if I was attempting to use the SpyderTV to calibrate my display. I can easily live with it if you or anyone else disagrees.

Bill,

Here is a post from glenned on the Eye-One that you may find useful.

http://www.avsforum.com/avs-vb/showthread.php?p=6243600&&#post6243600

Bill,

Here is a post where I posted some low light repeatability results with my Eye-One.

http://www.avsforum.com/avs-vb/showthread.php?p=5997199&&#post5997199

I would be willing to send my Milori Spyder2 to just such a shootout - as the only access I have to reference spectrometer is what Milori told me when they sent it - 0.001xy accuracy - which is 3x the marketed spec and 40x the ISF calibration requirements. This self promoting interest in this thread really has no place.

umr, this is a thread about the SpyderTV spreadsheets - exactly why do you need to bring up the EyeOne at all? Stick to the advance on colormath without disparaging peoples choice in equipment.

...umr, this is a thread about the SpyderTV spreadsheets - exactly why do you need to bring up the EyeOne at all? Stick to the advance on colormath without disparaging peoples choice in equipment.

Sorry. I was just trying to be helpful.

I only mentioned it as a quote in a previous post when Bill questioned my advice on using a comparator. I would never have mentioned it otherwise.

I think I will leave this discussion. A simple defense of my position seems to have generated much angst. Please continue without me and my biased perspectives.

Rader - Your XYZ->RGB matrix is transposed (compare your xy values against the CIE Gamut vs. what your RGB graph is telling you - e.g., 0.372 in y is noticeably green).

Ran though my first set of measurements using the Spyder in support mode and your spreadsheet. Thanks again for posting it and keeping it updated.

It was very cool to plug in the data see all these things about ones display. I can't speak to the veracity of the math and the approach but given the feedback from many of the forums experts it seems like you did a yeomen’s job.

I have a Sony 34HS420 and a BK Instruments HD Pattern Generator. What's nice about the BK is I can easily change display modes and am not tethered to my DVD at 480i. It can display 0 to 100 IRE at 2.5 increments which is certainly overkill. I did have some issues with the Spyder at 0 IRE but from what I have gleaned it may be better at 7.5. I hesitated pumping up the brightness for the sake of an accurate reading from the Spyder because I have the basic parameters set to what pleases my eye. I did not like the Spyder Wizards suggestions at all.

Most of the information is rather self explanatory but this deltaE thing is still a bit of a mystery, my green channel is really high relative to R and B. Guess I am gonna have to bone up on this. I will be taking a lot more measurements over the weekend. However, collecting data is one thing but interpretation and implementation, well that’s a different kettle of fish.

I had to transpose the matrix from the Poynton Color FAQ because he uses a XYZ column vector while I had used a XYZ row vector in my spreadsheet. Since transposing the product of two matrices is equal to taking the product of their transposes in the reverse order I also had to transpose the R709 XYZ->RGB matrix also for the product to work out.
I followed this - for two matrices A and B:
transpose(AB)=transpose(B)transpose(A)
It was easier for me to just transpose the 709 matrix than to redo the work I had done earlier with the matrices from Bruce Lindbloom (which assume a row vector XYZ). :)
The .372 y value isn't actually getting plotted because I only plot 10IRE through 100IRE. If you plug in .3127, .372 for one of the other IRE measurements it will show excess green.

Rader, have you considered including the dE(1994) in addition to the dE(1976) calculations? Reason I ask is becasue krasmuzik makes a good case in that the 1994 approach yeilds more useful information insofar as actual implementation of the data.

http://www.avsforum.com/avs-vb/showthread.php?t=586691&page=2&pp=30

I don't care for new 1994dE that was Ursa said that - anything beyond 1976 is not incorporated in any video standard. I prefer using the dC*, dH* and dL* measures based on 1976 CIE L'u'v' charts as they match your perceptions on video. I have tested this on customers and calibrators - and they do work to increase your understanding of what is wrong with the display. If you want to read about it more - see the sticky on calibration charts.

The enhancements to dE had to do with getting more accuracy at very precise surface color matches (paint/color) - they did that at the cost of larger inaccuracy for larger errors (you can even see this in Ursa data). Video has large errors and you do not worry about the tiny errors - the sensors cannot measure them well and you can only see it in side by side. Paint and textile is something you see side by side all the time - and in addition they are affected by the incoming light balance. Video IS the light - and there is a difference. Different strokes for different folks.

Paint and textile do not have to worry about their greens' being blue - they worry about it being off 0.00001xy blue. Video absolutely has to worry about the green's being blue.

It can display 0 to 100 IRE at 2.5 increments which is certainly overkill. I did have some issues with the Spyder at 0 IRE but from what I have gleaned it may be better at 7.5.


If you use the 'Avia' sheet to enter your measurements then make sure to use 7.5IRE as your black level or the gamma calculations will be way off.


Most of the information is rather self explanatory but this deltaE thing is still a bit of a mystery, my green channel is really high relative to R and B. Guess I am gonna have to bone up on this. I will be taking a lot more measurements over the weekend. However, collecting data is one thing but interpretation and implementation, well that’s a different kettle of fish.

Are you refering to the new sheet I added that allow measurements of primary and secondary colors (red, green, blue, cyan, yellow, magenta)? I just added that sheet in because I wanted to see how close my display was to HDTV spec (not even close :eek: ). Depending on your display type there might not be anything you can do about this. At least with my CRT there is no way to calibrate the primaries.
If you are looking at deltaE graph for the greyscale chart you just need to know that lower is better. You are better off trying to get a deltaE at or below 4 for the entire graph than for example having a deltaE of 0-1 for most of the graph with a spike at one point to deltaE of 20.
I am glad to hear you have found the spreadsheet useful.

Rader

Are the "correction factors" for Avia built into the spreadsheet?

No, not yet. As a rule I always take on twice as many projects as I have time to do. :)
If anyone wanted to take a stab at it using the link umr posted above to his web page I would be happy to work with them and integrate the changes.

I had to transpose the matrix from the Poynton Color FAQ because he uses a XYZ column vector while I had used a XYZ row vector in my spreadsheet. Since transposing the product of two matrices is equal to taking the product of their transposes in the reverse order I also had to transpose the R709 XYZ->RGB matrix also for the product to work out.

You're right. The presentation seemed off to me when I posted the above, but when I went back through your math, it's correct. I am entertained to note that you do RGB balance differently than either Jeff or I do it. AS we have covered before, there really is not a standard way to do this.

Later,
Bill

I don't care for new 1994dE that was Ursa said that - anything beyond 1976 is not incorporated in any video standard. I prefer using the dC*, dH* and dL* measures based on 1976 CIE L'u'v' charts as they match your perceptions on video. I have tested this on customers and calibrators - and they do work to increase your understanding of what is wrong with the display. If you want to read about it more - see the sticky on calibration charts.

To be clear, I am mostly agnostic on these things. I take a "use the hardest grading scheme available" approach to most things. If you use the 1994 method, then try to keep dE under 4 if you can. If you use the 1976 method, try to keep it under 4. If you use the CMC method, the same applies. If you use all three, then use the same rule. What is interesting is that they each have different tolerance ranges for what they deem to be error.

Later,
Bill

I just posted a new update which adds umr's correction factors for Avia. I also modified the relative RGB levels so that you can select red, green, or blue as your reference color. I find this a lot more useful for calibrating to D65. You just select one color (for example green) and then adjust the other two colors (red and blue) until you have minimized the error (deltaE) and gotten as close as possible to D65 greyscale.
I should also note that the Avia corrections only affect the Relative RGB chart and the gamma curve chart. The color temperature and delta E measurements will still be off.

Ursa

For using dE for calibrating it does not matter as your goal is no error. But if one is using dE for review purposes of factory presets - it does matter.

Ursa

For using dE for calibrating it does not matter as your goal is no error. But if one is using dE for review purposes of factory presets - it does matter.
Kevin - The problem is that, in practice, no error is infeasible. Poynton indicates that a dE of 4 is largely imperceptible under normal viewing conditions, and I don't dispute that. I do think that "normal viewing conditions" can change slightly, and so the appropriate dE method is debatable. If you trace out some of the math, under some circumstances, the 1976 formula indicates higher error, and under others, the 1994 formula indicates larger error. I merely take the max of either when I'm messing around with my H77.

Later,
Bill

I think I am now comfortable with the Spyders measurements and can live within it's margin of error. Found the Avia disk and took more measurements. The direction the spreadsheet took me was to increase RCUT on my Sony 34HS420 almost to it's SM limit. From a CRT perpective this means that the G2 aperture is set too high but I am concerned that increasing the CUT values may clip low level response. One thing I can say is that shadow detail is much better now.

My relative RGB error is now within a few percent from 20-100 (stimulus, IRE?) but the green error is fairly large between 10-20 , it looks exacly like your original spreadsheet when toggling the RGB Corrections. I realize that calculating these values have many different approaches but should they really vary that much?

Thanks again for your efforts.

I am not so sure about the Spyder's accuracy at low IRE levels. On my display I need to bump brightness by at least 5% for it to even take a reading at 10IRE and even then the xy values are all over the place. You might want to use a D65 calibrated computer monitor or Kodak grey card illuminated with a D65 light bulb to verify the low IRE levels look correct. I am also not 100% sure I implemented the correction values properly. That is part of the reason I left the option to toggle them on and off.
What are your deltaE values for the 20-100 IRE range? If it is 4 or below for that range I would call it good. DeltaE is a more useful metric for determining the quality of your calibration because it indicates the visible difference between your measured values and D65 grey.
Also if you run out of red cut, decreasing green and blue cut will have the same effect as increasing red.

Rader:

I thought there was a problem in version 6 with the dE calcs, am I wrong? Don't remember the exact dE values, datas at home, but the primaries were really high, way over 4. I still do not understand how to lower this, my white point is fairly close to D65 so I have no clue as to what to do next.

I was refering to the deltaE chart on the "Avia" tab which shows deltaE for the measured greyscale values, not the deltaE chart on the colors tab. I am reasonably confident in the deltaE calculation on the Avia and GetGrey tabs.

For low light measurement, you need to increase the read time on the Spyder. At the default 4 seconds, you will get lots of bad results. If you increase it to 9 seconds, then you get fairly good precision. Anyone using the stock read times should not be measuring much below 1 cd/m^2.

Later,
Bill

I don't recall seeing an adjustment for measurement time with the Spyder2PRO Studio software. How do you make that change?

Thanks



For low light measurement, you need to increase the read time on the Spyder. At the default 4 seconds, you will get lots of bad results. If you increase it to 9 seconds, then you get fairly good precision. Anyone using the stock read times should not be measuring much below 1 cd/m^2.

Later,
Bill

The PRO Studio software does not have any adjustments for timing, it takes about 5 seconds for it's readings

Try as I might I could not flatten out the relative RGB% from 0 to 20% IRE using xCUT settings. From 30 to 100 IRE I am within 2%. dE is under 4 from 30 to 100. The only thing I can surmise is that my low IRE meaurements are wrong using the Spyder. The values for Y from black, 10 and 20 IRE are 0.36, 0.76, 3.712 respectively. I am using a 9 sec read time per Ursa's recomendation. Any thoughts?

If you are under 4 dE from 30 - 100, then stop. You are done. Go watch a movie. Anything beyond this gets to tweak-itis, and you will find yourself chasing the bulb aging process with constant calibration.

Thanks Ursa, you made my wife quite happy. Rader, thank you for providing an essential tool, your hard work is much appreaciated. On to geometry!

New software update from colorvision, add temperature to "/support" window

>>>> SpyderTV 1.1.120 - international Windows (31,032.50KB, 4 downloads)
This is the installer for SpyderTV for Windows. (Nov. 2005) <<<<

I have Problems to understand about my Gamma.

I have Calibrate my Toshiba MT700 with SpyderTV and Ursas Spreadsheet- for STV.
I put the Values in the HD-D Sheet and before I have a Gamma about 2,74. After I get a Gamma from 2,38 but when I look a Film the Picture looks very bright and overall not good.
Now I have take the Values in Raders Spreadsheet- Model and there a very different Gammas at all.
Ursa-HD-D= 2,38
Rader Avia= 2,09 (confirm my impression from above)
Rader GetGray= 2,44

I think anything I haven't understood ore missing for me to see why there can so much differences between the Spreadsheet- Models. Have anyone a Answer for me, why this is so?

kindly Rgds Damdy

What are you using for your grey scale source patterns? Avia, Video Essentials, GetGrey's disk? You cannot use the same measurments for the Avia sheet and the GetGrey sheet in my spreadsheet. The Avia sheet assumes IRE test patterns while the GetGrey sheet assumes %stimulus. A 7.5 IRE test pattern is equivalent to a 0% stimulus grey test pattern.

What are you using for your grey scale source patterns? Avia, Video Essentials, GetGrey's disk? You cannot use the same measurments for the Avia sheet and the GetGrey sheet in my spreadsheet. The Avia sheet assumes IRE test patterns while the GetGrey sheet assumes %stimulus. A 7.5 IRE test pattern is equivalent to a 0% stimulus grey test pattern.

I use Ursas Test-pattern.
Ursa (I Hope he read this): Are they similar to one of the above?

Kindly Rgds Damdy

damdy

Just like we find there is different method of RGB% calculation, there is different method of gamma calc.

Hey guys can someone please correct me if i'm wrong. i've been using Rader's spreadsheet along with my Spyder2Pro colorimeter to try & get my LCD RPTV as close to D65 greyscale as possible. i try first to get my gamma curve close to the target (dashed pattern in the spreadsheet) by adjusting my tv's service menu RGAM, BGAM & GGAM. is this correct, because by just adjusting the Cuts & Drives, it seems to just change my color temperature & not my gamma.

thnaks guys.

Carmine.

The procedure you are following sounds correct to me. You should check with someone who knows the service menu controls on your set well to be sure.

Hey guys can someone please correct me if i'm wrong. i've been using Rader's spreadsheet along with my Spyder2Pro colorimeter to try & get my LCD RPTV as close to D65 greyscale as possible. i try first to get my gamma curve close to the target (dashed pattern in the spreadsheet) by adjusting my tv's service menu RGAM, BGAM & GGAM. is this correct, because by just adjusting the Cuts & Drives, it seems to just change my color temperature & not my gamma.

Hi Carmine,

While I am certainly not an expert in this area and can say only what I know to be true based on my experience with calibrating an HD CRT. I used CUT and DRIVE to adjust my color temperature though a gray scale ramp of 7.5 to 100 IRE. The color was off by moving my slider to zero. If your using composite you could always only leave Y plugged in to remove the color signal. CUT adjustmentd for lower IRE (7.5-50) while Drive (50+) for higher IRE.. After that I altered my GAMx to what the spreadsheet recommended and by what my eye deemed to look good, they are often not in total agreement.

A word of caution. I found myself going round and round at times with this calibrating thing, it is easy to become obsessive about it. So if your at a point where you like what you see and the data is close enough then your'e done. This is far from a exact science though many like to think it is.

I have Problems to understand about my Gamma.

I have Calibrate my Toshiba MT700 with SpyderTV and Ursas Spreadsheet- for STV.
I put the Values in the HD-D Sheet and before I have a Gamma about 2,74. After I get a Gamma from 2,38 but when I look a Film the Picture looks very bright and overall not good.
Now I have take the Values in Raders Spreadsheet- Model and there a very different Gammas at all.
Ursa-HD-D= 2,38
Rader Avia= 2,09 (confirm my impression from above)
Rader GetGray= 2,44

I think anything I haven't understood ore missing for me to see why there can so much differences between the Spreadsheet- Models. Have anyone a Answer for me, why this is so?

kindly Rgds Damdy

My method is, of course, correct! :D I will say that there are definitely different ways of calculating gamma. I included two, and they should agree within about 0.05 of each other if the gamma is smooth. If it is not, then the point measurements will be off considerably versus the regression. Also, since my stuff is not going to be released, then maybe we should take this off-line.

On a more general note, you should check whether set-up is present. If you are using AVIA test patterns, then the IRE levels should match using the NTSC disc (I do not have the PAL disc to verify whether set-up is there or not) with set-up included. If you are using the PC patterns, then ignore IRE altogether and compre the digital values versus what you are measuring against. My guess is that this is the culprit. Rader's model needs quite a bit more work to be a generalized model (e.g., HD vs. SD, PAL vs. NTSC). It can be done manually, but you need to know what to change where.

Later,
Bill

I tried to use Derek Smith's S2xyY utility with Sydertv, but it didn't work for me.
At first I start spydertv in support mode. When the colorimeter window has opened I start the s2xyy.exe with one attached ini. The name of the colorimeter tool changed and the s2xyY programm beeps and the s2xyy textfile is generated. I tried a couple of times to read the numbers from the support windows into the clipboard, but without success. I tried also some modification in the inifiles but textfile and clipboard are always empty.

I'm not shure if a make something wrong.

Thank's for your help

Peter

The S2xyY utility does not work with SpyderTV yet.

For now it will only work with the English version of OptiCAL V3 or Spyder2PRO V1 and V2.

I had requests for DVE support and PAL color space. They are in the newest copy at the top of the thread. Enjoy.

Thanks, much aprreciated. We will play with it in PAL territory and let you know. Now hopefully we get Derreckjsmith to support SpyderTV soon ;) .....

I had requests for DVE support and PAL color space. They are in the newest copy at the top of the thread. Enjoy.Pardon my ignorance, I have trouble understanding what one is supposed to do with the PAL Color space. I have DVE, PAL version. Where do I "tell" the spreadsheet that this is the case? I guess inserting the different values for IRE (by the way, you left %Stim for DVE, which I guess is a mistake) in the DVD sheet would work for NTSC.

Pardon my ignorance, I have trouble understanding what one is supposed to do with the PAL Color space.


You don't want to mess around with your color decoder until you have grey scale dialed in. I did not include instructions for the color sheets because I could not find much info on calibrating color decoders.
What I did was use the 75% red, green, blue, cyan, magenta, and yellow patterns from DVE to take xyY measurements for each color. I then used the user menu color decoder controls to adjust the levels of each color according to the "%error relative to green" chart. With my display I cannot change the xy coordinates of the primaries and secondaries (or just don't know how) so I left those alone.
To be honest I am not even sure if the color decoder sheets (HD, PAL, NTSC) are correct or useful. It is done to the best of my present understanding. Use them at your own risk and make sure you have a way to go back to your previous settings.



I have DVE, PAL version. Where do I "tell" the spreadsheet that this is the case? I guess inserting the different values for IRE (by the way, you left %Stim for DVE, which I guess is a mistake) in the DVD sheet would work for NTSC.

Use the DVE sheet. The DVE levels are %input for both PAL and NTSC. Avia is the only one that uses IRE patterns assuming the American NTSC 7.5IRE black level.
For DVE the patterns you want are title 14 chapters 2-7 and title 13 chapter 8 to measure black. Since they are full field patterns rather than window patterns I would recommend decreasing contrast from its normal level for the measurements.

hey rader thanks for the DVE update!!!! just a quick question regarding contrast & IRE set-up. If you lower contrast when using DVE, won't that throw off the grayscale calibration? also, i noticed you pointed out that you stated that when using Avia you want 7.5 IRE set-up, but what about DVE should i change my DVD IRE set-up to 0 IRE or leave it at 7.5?

thanks so much Rader & others on the forum!!!!
Carmine.

If you lower contrast when using DVE, won't that throw off the grayscale calibration?

In the ideal case no. In reality, possibly yes. IMO, it is better than the alternative of pushing the display to clipping which will really throw off your greyscale/gamma cuve.
Another alternative is to use the black, 20%, 40%, 60%, 80% full field patterns and then use the 100% window pattern (Title 14, chapter 8?) that comes right after the 100% full field pattern.

also, i noticed you pointed out that you stated that when using Avia you want 7.5 IRE set-up, but what about DVE should i change my DVD IRE set-up to 0 IRE or leave it at 7.5?


This is where it starts to get confusing. The use of IRE to describe the patterns in Avia has to do with the levels for each pattern on the disk, and is independent of the levels output by your player. For example, if you set your player to 0 IRE setup and then display the Avia 7.5IRE black field, your player will output 0 IRE. So set your player to whichever setting you want, calibrate contrast and brightness, and then take the measurements.
If you look at how IRE levels are converted to %input in the spreadsheet (starting at column B-56) it might make this a little more clear.

Since they are full field patterns rather than window patterns I would recommend decreasing contrast from its normal level for the measurements.Is this true for plasma screens as well? And thanks for all the great help. :)

Btw, what you wrote means that greyscale calibration is independant of PAL, NTSC or HDTV colorspaces? Did I get this right?

Thanks so much Rader for the clarification. I really appreciate your hard work on the creation of this indispensable tool for working with a Spyder colorimeter!!!!

Thanks again.
Carmine.

Is this true for plasma screens as well? And thanks for all the great help. :)


I was thinking of plasmas and CRTs in particular. I don't know about other display types.

Btw, what you wrote means that greyscale calibration is independant of PAL, NTSC or HDTV colorspaces? Did I get this right?


Yes, all use D65 white point and 2.2 gamma.

Rader,

I'm glad you put the disclaimer regarding the color tab. After putting my numbers in I found that my green was way off the chart (x0.267,y.709)! This certainly scared me a bit! I'll ignore it for now. Btw, one of your references lists "Original NTSC Color space" with very similar coordinates to what I have. So perhaps that is what my Display uses??? (reference: forum wouldn't let me post the url but it was on the videoessentials site)

I don't really know what I'm doing but I also set up my color decoder. I got all the color bars to match using the following method (on my original Grand Wega I, yes I know it doesn't have very good black levels...).

Technique (with avia and provided blue,green and red filters):

1. Use the blue color bars and a blue filter to set SCOL (color gain control) and SHUE (hue center control),
2. use the Red bars and red filter to set RYR and RYB,
3. use the green bars and green filter to set the GYR and GYB (in the MCP-ADJ2 group on the GW1).

I actually did that first and then turned the red/green panels off to verify SCOL and SHUE, turned the blue/green panels off to verify RYR and RYB, and the red/blue panels off to verify GYR/GYB. They required slight changes with the panel on/off method, but you really need to know how to navigate once you turn panels off so be careful!!!

Verified everything with the AVIA color decoder screen and it looked great!

If anyone knows that this method is wrong (or better yet if it is correct!), please let me know.

Anyhow, thanks a million for the spreadsheet Rader, it was an invaluable tool for setting up my display with the Spyder2Pro. I was able to get my %error to below 10% from IRE20 on (with deltaE either 1 or 2 from IRE30 up).

Looks great!
Rod

P.S. I got really bad results with the sensor on the screen, moved it back about 8 inches and it seemed to work much better (LCD rear projector).

Btw, what you wrote means that greyscale calibration is independant of PAL, NTSC or HDTV colorspaces? Did I get this right?
Yes, all use D65 white point and 2.2 gamma.

This is not correct. Grayscale calibration for PAL, SMPTE-C (NTSC) and HDTV will be different. You cannot move the location of the primaries and maintain the same white point without changing the relative balance of the primaries. You must re-balance the primaries for each display standard.

Play around with the XYZ->RGB matrices on Bruce Lindbloom's site to see what I mean.

Later,
Bill

Yes I know. My only interest in the XYZ -> RGB conversion is to generate to relative RGB error graph and red/green/blue gamma curves to serve as a visual aid to help the user know which color needs to move. Regardless of which transform is used the relative error graph will converge to 0% error at D65, and so far I have not found any xy data set that will tell you to move a color in the wrong way regardless of which conversion matrix is used.
Previously I had the three different XYZ->RGB matrices in the spreadsheet but later cleaned up and left only the r709 one. Through experimentation I found there was not much difference in the gamma and relative RGB error graphs between any of them. Will the gamma and RGB error curves move slightly? Sure. Will it make it any more difficult to adjust your display to D65? No. But you don't have to take my word for it - anyone interested in experimenting with the different colorspace conversions can find the transform matrices here: http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html
Just copy the XYZ to RGB matrix you want to use (PAL, SECAM, NTSC, etc) from the Bruce Lindbloom page into the cells in F56 through H58 on whichever spreadsheet tab you are using.
Lets also not forget that the primaries on the majority of consumer displays are no where close to any of the standard primaries and the blend to reach D65 will be different for each.

Now the $400 question... what would I be giving up by going the SpyderTV+rader's spreadsheet vs going with the SpyderTV Pro?

If the answer is "a big amount of time" and nothing else, I might live with it and $400 more in my pockets.

indeed what would be the real difference especially once derickjsmith supports spyderTV with his S2xyY utility???? I gues the wizards of SpyderTVPro. Anything else???

If there are no reliable readings for the black level or 10IRE...(and still visually the brightness seems to be adjusted correctly)....what would be the values to put in the sheet for those missing measurements....left open....zero ...or 0.313/0.329 ?

indeed what would be the real difference especially once derickjsmith supports spyderTV with his S2xyY utility???? I gues the wizards of SpyderTVPro. Anything else???Well... I hope somebody can answer the question.

It could be asked in a different way, since SpyderTV Pro isn't out yet: what could be missing from the SpyderTV+rader's spreadsheet that could be found in SpyderTV Pro?

If there are no reliable readings for the black level or 10IRE...(and still visually the brightness seems to be adjusted correctly)....what would be the values to put in the sheet for those missing measurements....left open....zero ...or 0.313/0.329 ?

I increase brightness, often by 10% or more until I can take reliable readings of at least the Y value. The SpyderTV /support menu simply will not read black or 10IRE on my display with brightness at it's normal level, even with a 9 second read time. This is really strange since brightness is set to the values the SpyderTV told me to set it to (which look great). This comes with the caveat that adjusting brightness may alter gamma or other parameters on your set. For the black measurement the xy values are not used in the spreadsheet, only Y. If you cannot measure Y for black then it is impossible to calculate gamma (see Umr's post a few pages back).
Another tip, it will be alot easier to take low level measurments using GetGrey or DVE since the 10% and 20% patterns on these disks are at a higher level than the 10IRE and 20IRE patterns on Avia.

Another tip, it will be alot easier to take low level measurments using GetGrey or DVE since the 10% and 20% patterns on these disks are at a higher level than the 10IRE and 20IRE patterns on DVE.
HUH?

O.K., I have been trying to get the gamma curve right on a Sharp LCD display and tried using Rader's spreadsheet for DVE but my calculations don't match the curves that come out on the spreadsheet ??
My manual calculations are per the attached pdf file but basically I'm taking the percent input (x) to the power of the gamma (y) that I want (in this case 2.2) to determine the light output percent of full output (100%).

For example, with 40% input and gamma=2.2, I get 13.3% (percent of full scale or 100% input).
When I plug this in the spreadsheet it comes up with a number like 18% light output=2.2 gamma ??

What am I missing ??

P.S. I'm using spyderTv with the support option and 9 second read time..

Todd

HUH?
Err.. I meant to say Avia in that last sentence. Avia levels are in IRE with black at 7.5 IRE, so the 10IRE pattern is equivalent to about a 2.7% pattern, and 20IRE is equivalent to about 13.5%.

Todd,
That PDF was an interesting read, thanks. The reason for the difference between what the spreadsheet reports and your hand calculation is that the spreadsheet uses the rec 709 transfer function instead of the simplified CRT gamma transfer function mentioned in the article. You can see how this is calculated by looking at how the target curve is generated in the spreadsheet. See umr's post a few pages back on why to use rec 709.

hey rader quick question. what are all the values below the gamma chart & how are the correctly used? i realize the left portion are the Ideal values, but how would i correctly interpret all the other values?

thanks so much.
Carmine.

Rader, there seems to be a difference in gamma results between measuring with avia (incl correction) or measuring with Finzel....am I mistaken...(or a wrong measurement on my side)?

noisemaker,
The values below the gamma chart are used to calculate the data for the graphs. There is not much reason to interpret them unless you want to understand how it works or verify my calculations (which I encourage :) ).
Arno,
Can you email me a copy of the spreadsheet with your data in it. It should not make that much of a difference whether you use Avia or Finzel. My email is listed on the first sheet.

hey rader, thanks for the reply pal. so, there is really no need for me to pay too much attention to REC 709 XYZ, McCamy's N, etc...?

thanks.
Carmine.

For the black measurement the xy values are not used in the spreadsheet, only Y. If you cannot measure Y for black then it is impossible to calculate gamma (see Umr's post a few pages back).
You are referring to Post #7 in this? If it is, then you are misinterpreting Jeff's statements. The issue Jeff was describing is that your calculations had previously assumed a true black (no light) black level, and that was materially impacting your overall calculated gamma. In reality, there are several viable alternatives for calculating gamma. Here are two:

1) Take a curve fit. In this case, you can ignore the linear tail when trying to match the measured curve to the ideal. What you do want here, though, is a sufficient population of measurement points to make your fit result more statistically significant. (This is what Gary was doing originally)

2) Measure point gammas. Given that you only have one unknown (gamma) for each measurement point, you can actually solve for gamma for each measurement point beyond the linear tail (there is no gamma factor inside the linear tail). This is essentially what you are doing now.

Neither of these methods equire there to be a black level (0%) reading to be valid. All that the black level provides is another data point. One would note, though, that using a regression esitmation technique, the error in white (high light output) will dominate the calculated gamma value given the absolute numbers involved (i.e., there is limited variation in absolute terms at low stimulus levels).

Later,
Bill

Thanks for the tip Bill - it would make things much easier if I figured out a way to calculate gamma without measuring black.

Is the gamma accurate in this? I put the same measured values into this spreadsheet and the resultant gamma was 2.45, but if I put them manually into ColorfactsPro I get about 2.1.

Can anyone verify either Colorfacts or this spreadsheets calculations are accurate?

TIA

Gary

I have similar experience ... in fact, I'm puzzled by the following equation which is widely used in the spreadsheet:-

measured value + 0.099/1.099

grateful if someone good at maths enlighten the crowd

Is the gamma accurate in this? I put the same measured values into this spreadsheet and the resultant gamma was 2.45, but if I put them manually into ColorfactsPro I get about 2.1.

Can anyone verify either Colorfacts or this spreadsheets calculations are accurate?Whoops! I honestly hope they are not wrong... I just spent two hours starting the calibration process... :eek:

News just in. :)

Thanks to some help from Jeff, it looks like the spreadsheet is just fine, as it conforms to Rec 709. CF may be using a simple power function calculation which is why the answers are different. I'll be interested to hear from the CF people regarding this as well.

Gary

I have similar experience ... in fact, I'm puzzled by the following equation which is widely used in the spreadsheet:-

measured value + 0.099/1.099

grateful if someone good at maths enlighten the crowd

The gamma calculation is based on the Rec 709 equation. See here:
http://people.ee.ethz.ch/~buc/brechbuehler/mirror/color/GammaFAQ.html#RTFToC5

The gamma calculation is based on the Rec 709 equation. See here:
http://people.ee.ethz.ch/~buc/brechbuehler/mirror/color/GammaFAQ.html#RTFToC5

Thx. Radar for the quick reply.

The reason why I raised the query is that I've done a monitor calibration with Spyder2Pro to a gamma value of 2.22 but when I tried to verify the calibration results by re-measuring (Colorimeter Tools), I got a gamma value of 3 on the GetGray sheet!! The funny part is that when I copy the 10-100 IRE results to the AVIA sheet w/o correction (and delete everything in the 0 IRE boxes), it gives me almost a gamma of 2.21! So, I'm still puzzled.

:confused:

Here's my measurement file.

AK,
I tried looking at your measurements and using the simplified CRT style gamma function it shows a gamma of about 2.4, which is still quite a ways off from what the Spyder2Pro set. I would attribute the Avia sheet reporting 2.21 as dumb luck - it can really only be used with Avia levels.
Besides that I can't give you a real answer. The Spyder2Pro did a nice job on my LCD computer monitors but it applied a funky correction curve to my CRT RPTV which resulted in lots of banding and washed out blacks. I may have done something wrong but after that I stopped using it.

Thx. Rader

I got the same value of 2.4 by changing the formulae in your spreadsheet, but I'm quite happy with the calibrated picture. It's time to re-calibrate according to Spyder2Pro's recommendations. This time I'll do the DVI as well. Hopefully, I'll get a closer match.

:)

BTW, I checked the primary color co-ordinates of my LCD monitor with Lumagen's internal test patterns and noticed a strinking color gammat with IRE. Is that normal?

Thanks for the tip Bill - it would make things much easier if I figured out a way to calculate gamma without measuring black.
Shawn - Looking at the sRGB specs, and trying to back into what some of the Rec709/SMPTE-C documentation says, seems to indicate to me that a gamma function is supposed to include the non-zero black level as part of the foundation for determining the theoretical gamma values. This was what Jeff was indicating. However, if Poynton is correct, then what you really want is for 99% stim to be JND* from 100%. Using CIE Luv, one could do a rough calculation of this (L*), but given the controversy over Delta E*, I'm not sure that this would necessarily produce a better answer than the analytical shorthand that Jeff (and I) use. It would certainly be more computationally intensive.

Alternatively, one could notice that when you normalize, you are usually using a fairly high number (reference white with my H77 runs between 400 and 500 cd/m^2). At that point, the 0.2 cd/m^2 black level is really a rounding error when we talk about normalization. If you use a curve-fit method (e.g., log-linear regression, preferably with >15 measurement points), then the rounding for black level and normalization pretty much get washed out.

So, basically start from 100% and calculate JND down to 0%, or go with a regression method to avoid having to measure a 0% value (even though it doesn't get used in most people's calculations other than to tweak the normalization process).

By the way, you should link directly to Poynton's site, rather than to a mirror. He's got some great stuff there that folks who are using your stuff ought to read.

Later,
Bill

* JND = Just Noticeable Difference

I purchased the SpyderTV last week and downloaded radar's spreadsheet. I had previously calibrated my Toshiba 42HP95 42" plasma with DVE and AVIA. The Spyder settings came out almost identical to what I had, except for contrast. It indicated a value of 82 (on a scale of 100), where I always had adjusted it to 40-50 range. I left it at 50. The Spyder also indicated a cool color temperature, which was to be expected.

I used the /support mode to do a complete gray scale alignment using radar's spreadsheet. The initial run showed a color temp of around 10,000 at level 10, then flattened out to about 7500 from 40 upward. RGB levels showed blue way high, green and red were not to bad. Gamma was very ragged.

After several more runs and adjustments to gray scale in the service menu, I got gray scale to within 200k of 6500k from 20IRE upward. RGB levels are within 5% from 20 on up. The total gamma is 2.33 and very smooth. DeltaE is from 1 to 4 from 20 upward. The 10IRE level has a color temp of 7500k and DeltaE of 14.

I calibrated through the component input with a 480p output from my DVD player. My question is this. Is my calibration accurate, even though the spreadsheet is set up for Rec 709, and I was sending the TV a non-HD signal of Rec 601?

To me, 6500k should be the same no matter what the primaries are. Am I correct, and please explain if I am not.

Thanks,
Duke

I purchased the SpyderTV last week and downloaded radar's spreadsheet. I had previously calibrated my Toshiba 42HP95 42" plasma with DVE and AVIA. The Spyder settings came out almost identical to what I had, except for contrast. It indicated a value of 82 (on a scale of 100), where I always had adjusted it to 40-50 range. I left it at 50. The Spyder also indicated a cool color temperature, which was to be expected.

I used the /support mode to do a complete gray scale alignment using radar's spreadsheet. The initial run showed a color temp of around 10,000 at level 10, then flattened out to about 7500 from 40 upward. RGB levels showed blue way high, green and red were not to bad. Gamma was very ragged.

After several more runs and adjustments to gray scale in the service menu, I got gray scale to within 200k of 6500k from 20IRE upward. RGB levels are within 5% from 20 on up. The total gamma is 2.33 and very smooth. DeltaE is from 1 to 4 from 20 upward. The 10IRE level has a color temp of 7500k and DeltaE of 14.

I calibrated through the component input with a 480p output from my DVD player. My question is this. Is my calibration accurate, even though the spreadsheet is set up for Rec 709, and I was sending the TV a non-HD signal of Rec 601?

To me, 6500k should be the same no matter what the primaries are. Am I correct, and please explain if I am not.

Thanks,
Duke


Excellent information and questions Mr. Duke. I too look forward to a response.

Try this discussion for a start:
http://www.avsforum.com/avs-vb/showthread.php?t=637711

Hello,

I used Rader's Spreadsheet along with a SpyderTV colorimeter and was able to use this successfully.

I have a question though. I used my DVD player outputting at 480P to my TV and using the DVE test patterns. Should I be using the Rec 709 or Rec 601 values? Rader's spreadsheet is set up for Rec 709 and I was wondering if I need to change it to use Rec 601 values? I have been looking around but haven't found a definitive answer.

The reason I ask is that looking at HD pictures, the color looks good. When I look at SD, the colors seem to be strong. Can't tell if I have a bad adjustment or just sh**ty D* feeds. Currently my OTA is set up to only receive digital channels and I couldn't get any HD shows on that last night (too late). Also I have a Samsung DVD that will upconvert and I did a quick check with it at 1080i (using spreadsheet, colorimeter, and test patterns) but I think that the color converter on the unit is not very good.

Thanks

It will not hurt anything to try switching the transform matrix to Rec 601. brucelindbloom.com has the transfrom matrices listed somewhere on his web page. I beleive you want the one listed as STMPE-C XYZ->RBG. Changing the R709 transform matrix will only change the shape of the color error graph and gamma curves.
Regardless of which color space you use the end goal is to get the (x, y) values as close to (.313, .329) as possible. The Delta-E graph is what tells you how accurate your picture is (lower is better) and it is not based on R709. The big caveat here which I have probably not pointed out as much as I should have is the Avia correction factors in the spreadsheet do not correct the Delta-E graph.

Anyone using this with the built in test patterns in a Lumagen scaler? If so which tab in the spreadsheet is most appropriate (DVE, GetGray,Avia)?

Thanks,

Shawn

I would think the one that corresponds to the test disk you are using.

Gary

" I would think the one that corresponds to the test disk you are using."

That was the point, not using a test disk. I wanted to see about using the built in internal test patterns in my Lumagen scaler for calibration......

Shawn

Ah, I see your point :)

Getgrey;s are more accurate than Avia, so that woule probably be the best one to use. I didn't realise he now had a DVE tab on the sheet. What are the differences between DVE and GGs?

Gary

" I would think the one that corresponds to the test disk you are using."

That was the point, not using a test disk. I wanted to see about using the built in internal test patterns in my Lumagen scaler for calibration......

ShawnBear in mind that in this case you would just be calibrating the output of the scaler to the display, not taking into account your source. If the source is digital, then probably no big deal. If the source is analog you might have miscalibration. Take this with a grain of salt, but it is as I currently understand it (I have an HDP too).

Yup, all my important sources to the HDP are either DVI or SDI so I'm not terribly worried about the source calibration. My plan was to get the projector calibrated using both the projectors controls and the greyscale functions in the Lumagen as needed. Then double checking the simple settings on the source and adjust them either at the source itself or using the per input functions in the Lumagen.

Shawn

= What are the differences between DVE and GGs?

Gary

The DVE tab has levels at only black, 20%, 40%, 60%, 80% and 100%. The tab is for the non-pro version.

Thanks Rader. :)

Gary

Hi all

Do any of you have suggestions on what to read so I can use SpyderTV correctly and understand what’s going on with the data as I experimented taking readings last night with xbox360 dvd player on av1 using avia and from what I understand they where way out so out the gamma curve was all over the place so its definitely something I’m doing and need to lern more.

Tks, Rader. will try your spreadsheet and hope can figure out by myself.
SpyderTV user.

BTW, still confused the temp definition by different makers. :confused:
warm = high temp
or warm = low temp?

Most manufacturers relate "warm" to a lower color temperature. With many displays even "warm" is still too high. I used the SpyderTV and radar's spreadsheet on my Toshiba 42HP95 plasma, and found the "warm" setting produced a color temp of 7500. I was able to correctly adjust it using the service menu though. Also when using the spreadsheet, the actual x, y coordinates are the most important for setting gray-scale and getting the proper colors. Get those DE values as low as possible.

I think radar's spreadsheet is a great contribution to all of us do-it-yourself calibrators. And the input from many others about the spreadsheet (especailly URSA and UMR) has been fantastic! Maybe the SpyderTV and spreadsheet aren't quite as good as a well done ISF calibration, but they appear to be close, and it sure is fun to DIY!

Duke

Nice work rader!

I've been using your sheet with my Spyder2pro to calibrate my new Dell 2405 LCD monitor... warm-up exercise before tackling my Pio 1130HD. (I went with the spyder2pro over the spyderTV because I also wanted to calibrate my printer, so I went with the Print Pro Suite).

For those of us using this on our computer monitors, any chance of adding an sRGB colorspace tab?

Cheers!

Nice work rader!

I've been using your sheet with my Spyder2pro to calibrate my new Dell 2405 LCD monitor... warm-up exercise before tackling my Pio 1130HD. (I went with the spyder2pro over the spyderTV because I also wanted to calibrate my printer, so I went with the Print Pro Suite).

For those of us using this on our computer monitors, any chance of adding an sRGB colorspace tab?

Cheers!
eh?,
How exactly are you using Rader's spreadsheet to calibrate the dell 2405FPW? I have the same monitor, and all settings (except brightness) is disabled when connected through DVI? Are you just profiling the video card. You can just use the Spyder Pro wizard to do that without using the spreadsheet? Please explain...

I'm adjusting the red/green/blue sliders.

I adjust the sliders, and then take readings using the colorimeter tool setting the window at various grey levels (51, 51, 51; 76, 76,76; 102, 102, 102; etc) and input the readings for xyY and colour temp into the spreadsheet to track Gamma, Colour temp, and Delta E

The thing I have noticed is that the wizard sets you up with a colour profile which is near bang on for the gamma, but not so good on the Colour temp... mine usually comes in at around 6700 -

Setting up the monitor on my own, finding the right relative and absolute levels of RGB, using the sliders, I can get a much better overall colour temp (between 6400-6600)- but the gamma is slightly off (2.23 for red and green, 2.19 for blue)

I'm adjusting the red/green/blue sliders.

I adjust the sliders, and then take readings using the colorimeter tool setting the window at various grey levels (51, 51, 51; 76, 76,76; 102, 102, 102; etc) and input the readings for xyY and colour temp into the spreadsheet to track Gamma, Colour temp, and Delta E

The thing I have noticed is that the wizard sets you up with a colour profile which is near bang on for the gamma, but not so good on the Colour temp... mine usually comes in at around 6700 -

Setting up the monitor on my own, finding the right relative and absolute levels of RGB, using the sliders, I can get a much better overall colour temp (between 6400-6600)- but the gamma is slightly off (2.23 for red and green, 2.19 for blue)
Are you connected through VGA? When I connect through DVI, all monitor controls except Brightness is disabled. Are you talking about color bars on the monitor or the Video card display profile?

Connected through DVI - Under the "Color Settings" not under the "Image Settings" menu for the monitor.

Shawn - Looking at the sRGB specs, and trying to back into what some of the Rec709/SMPTE-C documentation says, seems to indicate to me that a gamma function is supposed to include the non-zero black level as part of the foundation for determining the theoretical gamma values. This was what Jeff was indicating. However, if Poynton is correct, then what you really want is for 99% stim to be JND* from 100%. Using CIE Luv, one could do a rough calculation of this (L*), but given the controversy over Delta E*, I'm not sure that this would necessarily produce a better answer than the analytical shorthand that Jeff (and I) use. It would certainly be more computationally intensive.

Alternatively, one could notice that when you normalize, you are usually using a fairly high number (reference white with my H77 runs between 400 and 500 cd/m^2). At that point, the 0.2 cd/m^2 black level is really a rounding error when we talk about normalization. If you use a curve-fit method (e.g., log-linear regression, preferably with >15 measurement points), then the rounding for black level and normalization pretty much get washed out.

So, basically start from 100% and calculate JND down to 0%, or go with a regression method to avoid having to measure a 0% value (even though it doesn't get used in most people's calculations other than to tweak the normalization process).

By the way, you should link directly to Poynton's site, rather than to a mirror. He's got some great stuff there that folks who are using your stuff ought to read.

Later,
Bill

* JND = Just Noticeable Difference

I'd strongly suggest anyone who is really trying to learn about color and calibration actually just buy Poynton's book. It is a great reference.

Ah... well.. to answer my own question - it looks like sRGB is identical to the HD Color (rec 709) colour space, so I can just use that - n'est pas?

Thanks to rader's spreadsheet and this thread, I tackled calibrating my Sony 36HS420 with the Spyder2PRO with the Avia disc.

The issue of gamma came up and I decided to ignore it on the first pass. The Spyder2PRO won't give me any useful readings until 30IRE on the Avia disc. I read the instruction to increase brightness until a reliable reading can be taken, but I'm not sure how useful that is.

My question: should I just use Avia and bump up the brightness on the 0-20IRE window patterns? Will this put me 'in the ballpark' for gamma readings? And do I bring the brightness back down to calibrated level for 30IRE and above? Or should I use DVE instead. From what I've read DVE has higher average output level - will this allow a better stab at gamma?

Not being technically proficient enough with the concept of gamma, I don't know if this bumping up the brightness trick would elicit useful results or not.

Thanks,


Jeff.

Jeff,

Bumping brightness is likely to distort the gamma measurement. You need good light readings from 10 to 100 percent and a reasonable 0 to determine gamma accurately.

umr;

Thanks for the reply. So what would you do - just ignore the gamma issue? There's no way around the problem - the Spyder2PRO just can't read such low light levels. It seems to me, rather than using flawed results, I should just calibrate grayscale as best I can from 30-100IRE, maybe getting some Kodak cards to compare the low end for colour, and just forget gamma. If I can't do it right, I'd probably do more harm trying with the wrong tools! :)


Jeff.

Jeff,

Ignoring gamma can be a big mistake. It is a huge component of a quality image. I would find some way to measure your light levels. An AEMC light meter would work for this.

OK I have a tough one here, anyone know how to increase the spyder2pro read time when using it with Mac OS X? I am sure there is a file that can be edited but I have no idea where it is.

Hey guys, I spent several hours today tweaking. This is what I ended up with. What do you think?

Jeff,

Ignoring gamma can be a big mistake. It is a huge component of a quality image. I would find some way to measure your light levels. An AEMC light meter would work for this.

Jeff, which light meter do you use?

Jeff, which light meter do you use?

I normally use a Gretag Macbeth Eye-One Pro spectroradiometer. It is a good light meter and color measurement tool. It has sensitivity with my software to about 0.02 fL or 0.5 lux with my custom diffuser which is low enough to not cause large gamma calculation errors.

Hey guys, I spent several hours today tweaking. This is what I ended up with. What do you think?

Your mid and high range is all over the place. How are you making the adjustments? Is there any ambient light?

Is it really bad? I could get it smoother but then the total gamma was too high. That seemed like the best compromise. No there is no ambient light in the room. I have total light control. I might take another stab at it tomorow, what do I need to adjust exactly to fix that.

Jeff,

That gamma is not good, but if you bought that device to get a good calibration on an LCD projector you are likely to be off in other ways as well so I would not sweat it. You are getting what you paid for. That tool is more for fun than anything else.

Jeff,

That gamma is not good, but if you bought that device to get a good calibration on an LCD projector you are likely to be off in other ways as well so I would not sweat it. You are getting what you paid for. That tool is more for fun than anything else.

What could I get that won't break my account?

What could I get that won't break my account?

Nothing short of thousands of dollars according to UMR. Read the thread that is linked in his profile.

The real question is, can this tool actually help achieve results you are satisfied with.
I have seen drastic improvements while working with mine. Currently I am struggling with the service menu options of my Samsung HL-S5687W. If I could figure out the controls that would affect color brightness I believe I will be satisfied.

ISF calibration is out of the question for me. Guess that old fishing proverb holds me up.

The cheapest option is just to hire someone who has the equipment and knows what they are doing. Whether buying the necessary equipment would break your account is not something I have any knowledge of. Here are some peoples experience with both options.

http://www.avsforum.com/avs-vb/showthread.php?p=7232331#post7232331

http://www.avsforum.com/avs-vb/showthread.php?p=7456718&&#post7456718

http://www.avsforum.com/avs-vb/showthread.php?p=6918504&&#post6918504

Based on my own tests and seeing the results in the field from other people using other sensors I would only use what I use and that is a Gretag Macbeth Eye-One Pro with my software and an AccuPel HDG3000 video generator.

You are also only solving one half of the problem if you have a surround sound system. Calibrating audio is another complex task requiring more tools.

You are also only solving one half of the problem if you have a surround sound system. Calibrating audio is another complex task requiring more tools.

This part I've got covered. Behringer DEQ 24/96 PEQ/RTA, Yamaha RXV-2600, DIY sound panels, dual subs, Paradigm all the way around except for subs.

So basically what you are saying is this spyder2 pro colorimeter I just bought is junk and I will never get a good calibration with it, even though it is marketed as usable for a front projector? I wish I would have known this before I spent 200 bucks.

This part I've got covered. Behringer DEQ 24/96 PEQ/RTA, Yamaha RXV-2600, DIY sound panels, dual subs, Paradigm all the way around except for subs.

So basically what you are saying is this spyder2 pro colorimeter I just bought is junk and I will never get a good calibration with it, even though it is marketed as usable for a front projector? I wish I would have known this before I spent 200 bucks.

You definitely have good equipment for audio.

Junk is probably too strong a word. I would say it is questionable. My experience is that these types of instruments will be reasonable on a limited number of displays and unless you happen to be lucky you will not get good results on color calibration. It is even possible that you will make things worse than where you started. These devices have also not been very color stable making there usefulness more uncertain as time progresses with no way to know when it should not be used or recalibrated.

Jeff, would I be best then in just getting the greyscale to track as accurately as I can in just ignore the gamma number that I see because it may not be accurate anyway? Does this sound reasonable?

Pic here

Jeff, would I be best then in just getting the greyscale to track as accurately as I can in just ignore the gamma number that I see because it may not be accurate anyway? Does this sound reasonable?

Pic here

It is impossible for me to specifically advise you on this without seeing what is going on with your display.

Gamma is extremely important for quality PQ and should not be ignored. I would try numerous things to get a good gamma, but all displays will not deliver a reasonable gamma. I will not even work on a display more than once that will not allow the gamma to be set reasonably. The problem is that poor gamma distorts the complete look of the image and usually adds artifacts like posturization. The problem is that 8 bit video is very marginal and any significant distortion to the luminance curve will result in obvious problems.

Getting your gray scale to track well is only one of the goals. My primary goal is to track around D65 without a significant green error. Your instrument will track well given sufficient light, but you do not know where you are relative to D65. Worst case I would expect you to have as much as 10% too much green in your gray scale based on a maximum error of +0.018 in y. This level of error corresponds to a delta E u*v* of 15 which is much larger than a value of five which is what I consider to be in tolerance.

Looking at reviews, service and operating manuals for your projector I have the following opinions.

- There appear to be sufficient controls to get a great picture.
- The original gray scale can be half the +0.018 maximum error for a filter based color analyzer.

Yes it does have a lot of settings. I may get it ISF calibrated first then get some better gear later on. I am going to play some more and see if I can smooth it out.

Yes it does have a lot of settings. I may get it ISF calibrated first then get some better gear later on. I am going to play some more and see if I can smooth it out.

Good luck! Great color performance is a rare and wonderful thing to see.

I played some more and ended up with this. The picture looks great on HD and DVD. I don't think I can get it any better with what I have so I am going to leave it as is and get it ISF calibrated in the near future.

aidioholicjeffL,
Just out of curiosity, what did your before calibration run look like?

aidioholicjeffL,
Just out of curiosity, what did your before calibration run look like?

Awful, the gamma was way below the target, and not very smooth. The RGB levels were all over the place.

Just curious...what did you change to improve from last graph....contrast?

Everything, RBG cuts and drives, and all 3 gamma settings low, mid and high.

Everything, RBG cuts and drives, and all 3 gamma settings low, mid and high.
What set are you calibrating?

What set are you calibrating?

Panny 900u projector on a 106 diag carada BW screen.

question about the spreadsheet. I calibrated a display and the average (r, g, and b) gamma was 2.5. however when I change the target gamma to 2.5, my luminance curves versus %stim do not match. target gamma set to 2.2 agrees better in that plot. What might not not understand or be doing wrong?

jeff

I'll answer my own question. I believe there's an error in the formulae calculating the gamma. I've corrected it in my version and the numbers now make sense.
in Cell P72, for example, make the formula look like:

=LOG(M56, 10)*LOG(B56, 10) instead of =LOG(M56, 10)*LOG((B56+0.099)/1.099, 10)

specifically, change (B56+0.099)/1.099 to B56, for cell P72. Change all formulas that look like this, in this way and you'll be good to go.

Best,
jeff

I'll answer my own question. I believe there's an error in the formulae calculating the gamma. I've corrected it in my version and the numbers now make sense.
in Cell P72, for example, make the formula look like:

=LOG(M56, 10)*LOG(B56, 10) instead of =LOG(M56, 10)*LOG((B56+0.099)/1.099, 10)

specifically, change (B56+0.099)/1.099 to B56, for cell P72. Change all formulas that look like this, in this way and you'll be good to go.

Best,
jeff

It looks better...BUT is the calculation still correct ?

Yes the calculation is correct. From the source used for the spreadsheet calculations, http://www.brucelindbloom.com/index.html?Equations.html, you can see that the calculations are correct.

The intent of those extra factors was to protect against taking the log of a small number, but the way they (creators of the spreadsheet) did it is incorrect. In fact, there is no need to protect against small numbers if you look at what the source values are. The proper way to implement protection for some occurance is to do it in such a way that for arguements that need no protection you get the same answer whether you protect or not. This is clearly not the case with what was in the spreadsheet. You can test that for yourself.

Best,
jeff

Also, I've emailed rader about the corrections and emailed him my corrected version. I'll leave it to him to post the updated version.

Best,
jeff

Also, I've emailed rader about the corrections and emailed him my corrected version. I'll leave it to him to post the updated version.

Best,
jeff


Would love to try it on the data I have got from previous measurements...PM?

When I plugged in my numbers my gamma went from 2.30 to 1.83 with the new sheet. That might explain why I thought my picture looked a little washed out at times.

I thought the latest Rader sheet was using the Rec709 gamma calc? Greeno - are you using a simple power function for calculation? I'm not very familiar with gamma but a little info might help me understand what the difference is (i.e what was the Rader sheet actually using?). Thanks

Gary

I always cal to 2.5 as well. Supposedly to compensate for "dark surround" conditions but I actually prefer it regardless. ( although this may be down to the simple fact I never look at any display in anything but a dark enviroment , work or home. Does wonders for the tan too).

I think he's saying the equation that maps the transfer function to the target gamma is incorrect on the spreadsheet ...if you modfiy it away from 2.2?

I gave up smoking equations years ago myself so its all greek to me.

I think he's saying the equation that maps the transfer function to the target gamma is incorrect on the spreadsheet ...if you modfiy it away from 2.2?



Ah, gotcha. I really should get my head around the calcs at some time though I think.

Gary

If you want a good (simple) explanation of display gamma, look at the link below.
http://www.sencore.com/newsletter/June04/Gamma.htm

Todd

Thanks for the link. Combined with Poyntons Gamma faq I might understand the calculations a bit better now :)

Gary

OK after reading that Sencore doc and the posts in this thread I am confused. :confused: Do I or do I not have to get a reading from 0 to 100 to accurately calculate gamma? After Reading that doc I would say not.

Yeah kind of , but as "gamma" itself is just a simplification of the "straight line curve" part of the transfer function its hardly accurate in its own terms. The transfer function itself is not definable as an easily expressed exponent so they grab the easiest bit of the curve to quantify and broadly define it as a gamma for neatness and ease of describing deviation away from the idealised transform.

I found a nice article here:
http://www.ebu.ch/en/technical/trev/trev_frameset-index.html and choose "257-Autumn 1993". they provide a differential way to calculate gamma that avoids most of the issues with constant offsets that are very difficult to determin. I 've used it on my data and it is pretty bullet-proof.

Best,
jeff

hey quick question on your revision to rader's sheet...
am i supposed to change just cell P72 or all cells P72-P81,R72-R81 & T72-T81?

Thanks!I'll answer my own question. I believe there's an error in the formulae calculating the gamma. I've corrected it in my version and the numbers now make sense.
in Cell P72, for example, make the formula look like:

=LOG(M56, 10)*LOG(B56, 10) instead of =LOG(M56, 10)*LOG((B56+0.099)/1.099, 10)

specifically, change (B56+0.099)/1.099 to B56, for cell P72. Change all formulas that look like this, in this way and you'll be good to go.

Best,
jeff

Actually you'll notice that I deleted my posting of my corrected version of the spreadsheet. After more analysis, including using the differential method of calculating gamma I linked above, I am not happy with my corrections either. I think there's an issue not accounting for a finite Y at 0%. The differential way above is more robust and does not care about constant offsets, since it is based on derivatives.

so at rader's suggestion, I agree that the spreadsheet should stand as it originally was. It can easily be modified to perform off-line analysis (add it in yourself) of the data to estimate gamma. I'm now doing that using the differential method.

Sorry for the confusion,
jeff

I have a Spectrascan 650 spectroradiometer (I use it for my business) and plan to use it to try to calibrate my Ruby. Can I use the reflectance mode off of my Stewart Firehawk? I would like to do this to eliminate any screen influence but am concerned about any unintended influences (low light level readings, etc.).

Please offer any additional suggestions.

Thanks.

Actually you'll notice that I deleted my posting of my corrected version of the spreadsheet. After more analysis, including using the differential method of calculating gamma I linked above, I am not happy with my corrections either. I think there's an issue not accounting for a finite Y at 0%. The differential way above is more robust and does not care about constant offsets, since it is based on derivatives.

so at rader's suggestion, I agree that the spreadsheet should stand as it originally was. It can easily be modified to perform off-line analysis (add it in yourself) of the data to estimate gamma. I'm now doing that using the differential method.

Sorry for the confusion,
jeff

Actually, I liked your corrections (going back to Lindbloom's equations), but did notice that the "best fit" curve fitting of gamma in the spreadsheet was influenced strongly by the numbers at low % stimulation (because the values of the logs are so large for small numbers). I ended up with a gamma curve that appeared to be right on except for small deviations at 10% & 20% stimulation, but the calculated gamma was 2.10 instead of 2.2. When I changed the spreadsheet formula to calculate gamma from 20% to 100%, the result was gamma = 2.17.

I'll have to look at the differential method to see what that gives.

Thanks for the interesting information -- made me stay up half the night last Friday looking at formulae and reference material!

Thanks.
to summarize the differential method:
1) assume Y = P^gamma
2) differentiate dY/dP = gamma P^(gamma-1)
3) take log, log(dY/dP) = log(gamma) + (gamma-1) log(P)
4) fit a line to this and the slope is gamma-1. ignore the log(gamma) constant as it's not really log(gamma), it absorbs another offset or two that we don't care about.

When I use this method with my data, I get a gamma that's right on target, and I'm using all the data. note though that when using forward difference for example, if you start with N points of data, you'll have N-1 points of derivative data.

Best,
jeff

"to summarize the differential method:
1) assume Y = P^gamma
2) differentiate dY/dP = gamma P^(gamma-1)
3) take log, log(dY/dP) = log(gamma) + (gamma-1) log(P)
4) fit a line to this and the slope is gamma-1. ignore the log(gamma) constant as it's not really log(gamma), it absorbs another offset or two that we don't care about."


can this be done in a spreadsheet? I've never tried to do differentials in Excel... :eek: ?????

there's an easy way. excel has a function called "linest(yvalues,xvalues)" that returns the slope of a set of y,x values, i.e. it assumes it's a line. differentiating data, use the forward difference formula: (y(i+1)-y(i))/(x(i+1)-x(i)), with x(i+1)-x(i) != 0

use x as %stim (a number between 0 and 1) and y as Y normalized by Y at 100%stim.

differentiate as above. take the log and feed the values into linest(,).

Gulp.... :eek:

Thanks !! :D

there's an easy way. excel has a function .....


Ever since my first graduate p-chem class, I have always dreaded the phrase:

There is an easy way.....

This was usually followed by a weeks worth of frustration trying to complete the single assigned problem.

niesman

IMHO, there's a fundamental flaw in normalization of Y the way it's done in the spreadsheet. Try performing same normalization to a perfect 2.22 Gamma Y curve(assuming black level measurement is taken at 7.5IRE) and the resulting curve gamma will be much lower!

The correct way (IMHO again :) ) would be to find what is the Bias(Bi) and the Gain (Ga) of the measured Y curve are and normalize as follows:

Ynorm = (Y-Bi)/Ga.

The Y that we measure is (S=stimulus > 0.081):

Y = Ga*(S+0.099/1.099)^gamma + Bi

Black level S=0.075 (assuming it's calibrated correctly) and according to REC709 (linearity below 8.1%):

Yblk = Ga*(0.075/4.5) + Bi
Ypeak = Ga*1 + Bi

Solving this set of equations is easy. You can have a look in the attached spreadsheet - comments are welcome!

BTW, Can anyone tell me why do I get this greenish look to all the movies once I'm closing in on D65 (even with the original gamma calculation)? :(

Ok, I tuned my setting using the SpyderTV walkthrough, then I did the gamma and color readings with DVE. My gamma appears to be way off, how do I correct this? The colors look ok, seems that I have a bit of green push.

Also, when attempting to calibrate grayscale, do I turn the color down to zero on my set?

IMHO, there's a fundamental flaw in normalization of Y the way it's done in the spreadsheet. Try performing same normalization to a perfect 2.22 Gamma Y curve(assuming black level measurement is taken at 7.5IRE) and the resulting curve gamma will be much lower!

The correct way (IMHO again :) ) would be to find what is the Bias(Bi) and the Gain (Ga) of the measured Y curve are and normalize as follows:

Ynorm = (Y-Bi)/Ga.

The Y that we measure is (S=stimulus > 0.081):

Y = Ga*(S+0.099/1.099)^gamma + Bi

Black level S=0.075 (assuming it's calibrated correctly) and according to REC709 (linearity below 8.1%):

Yblk = Ga*(0.075/4.5) + Bi
Ypeak = Ga*1 + Bi

Solving this set of equations is easy. You can have a look in the attached spreadsheet - comments are welcome!

BTW, Can anyone tell me why do I get this greenish look to all the movies once I'm closing in on D65 (even with the original gamma calculation)? :(

This is one reason why the differential method I linked above is very useful. Normalization and zero values (well sort of) have no effect since you're fitting to a derivative.

The greenish tint issue could be a sensor calibration issue. I had a sensor whose calibration had drifted and it produced "calibrated" results that were green tinted. Gamma has nothing to do with D65, although it affects grayscale tracking across %stim.

Best,
jeff

Greeno, I've read the method - what I'm suggesting is just a simplification of the same approach. Did you manage to implement the whole algorithm they describe in the article in Excel?

As for the "green push" - how did you overcome the sensor calibration issue? (I know it's got nothing to do with gamma).

I'm going crazy here :( It's been seventh night in a row I'm trying different RGB cut/drive values, but always end up with a green tint :eek:

This is one reason why the differential method I linked above is very useful. Normalization and zero values (well sort of) have no effect since you're fitting to a derivative.

The greenish tint issue could be a sensor calibration issue. I had a sensor whose calibration had drifted and it produced "calibrated" results that were green tinted. Gamma has nothing to do with D65, although it affects grayscale tracking across %stim.

Best,
jeff

So in theory if I can adjust the gain and bias for each color to achieve the perfect value for red, blue, and green then my grayscale values should be 100% correct right?

My "calibrated" settings that produced a green tint in blond hair and some explosion firelballs came about when using an old dtp-92 - not the current dtp-94. The way I got rid of the green was to use a calibrated meter, the dtp-94.

There was a clear green tint when I measured grayscale using the dtp-94 AFTER calibrating the set using the dtp-92. Re-calibrating with the dtp-94 solved the problem.

I did implement the main part of the differential method. Who cares about the intercepts? What we're after is the (gamma-1). that is what I've implemented.

Best,
jeff

Once you have a SpyderTV sensor and this spreadsheet and you get the xyY values from SpyderTV and input them to compare to the spreadsheet, how do you know what settings to tweak to bring them back into focus?

Greeno, I'm sorry to tell you that, but I checked the differential method and it doesn't work very well. Take a perfect 2.2 gamma dataset, sample it in a few points (the ones you get with Avia or DVE) and run the algorithm - you'll get a higher than 2.2 number. (I've checked it with DVE samples of 20,40,80,100 and got an error of ~0.2)

The reason is that Y1-Y2/(X1-X2) isn't really a dY/dx, but an approximation. Since we've got pretty few points, the total error is big. I'm guessing with Avia it will be smaller though (more sampling points).

This method will work well when you have a lot of sampling points.

The original raider's method (bar small number correction) combined with my BIAS/GAIN calculation gets much closer result (easily verified even visually comparing the reference and the acquired gamma graphs).


My "calibrated" settings that produced a green tint in blond hair and some explosion firelballs came about when using an old dtp-92 - not the current dtp-94. The way I got rid of the green was to use a calibrated meter, the dtp-94.

There was a clear green tint when I measured grayscale using the dtp-94 AFTER calibrating the set using the dtp-92. Re-calibrating with the dtp-94 solved the problem.

I did implement the main part of the differential method. Who cares about the intercepts? What we're after is the (gamma-1). that is what I've implemented.

Best,
jeff

Of course you're right that a forward difference is only a first order approximation and will improve with more data. In my testing on 4-5 dataset (and I also played with an ideal curve or two), I get a gamma approximation (average of the pointwise values) that is spot.

I don't have your implementation so I can't judge it, nor do I want to. I offered this reference up just to provide some additional technical info that avoids the problems associated with more simplistic ways of calculating gamma.

Thanks for the feedback.

Best,
jeff

Can anyone take a look at my speadsheets for a standard GetGray calibration, versus my SpyderTV calibration? I would like to know which is more accurate. I attached both speadsheets in the zip file.

Thanks!

just want to say thanks to everyone in this forum, Brian Hampton for his ancient writeup on calibration, URSA, the faq's, radar the spreadsheet maker, I've personally been gathering and trying to understand/absorb as much about grayscale and color temp calibration as I could the past few days.. a subject I admit I wasn't really that interested in before since it involved delving into the service menu and I just didn't want to spend my time deciphering every single SM setting there was :p I'd rather be enjoying my set

anyhows since I got a Sony KDL-40xbr2, where there was surprisingly White Balance controls in the user menu, I knew right away that this was it.. so I tried reading as much as I can and absorbing stuff and eventually I jumped into it

anyhows my previous avia calibrations:
http://fate-owns.us/imgs/misc/HomeTheatreIsht/kdl-40xbr2/googly-avia-colortemp1.jpg
http://fate-owns.us/imgs/misc/HomeTheatreIsht/kdl-40xbr2/googly-avia-rgb1.jpg
http://fate-owns.us/imgs/misc/HomeTheatreIsht/kdl-40xbr2/googly-avia-gammacurve1.jpg

I wasn't really that satisfied so I did things over again under DVE:
http://fate-owns.us/imgs/misc/HomeTheatreIsht/kdl-40xbr2/googly-dve-6500k.jpg
http://fate-owns.us/imgs/misc/HomeTheatreIsht/kdl-40xbr2/googly-dve-rgblevels1.jpg
http://fate-owns.us/imgs/misc/HomeTheatreIsht/kdl-40xbr2/Googly-DVE-gamma1.jpg
http://fate-owns.us/imgs/misc/HomeTheatreIsht/kdl-40xbr2/googly-dve-gammacurve1.jpg

now is it *perfect* ? No.. it is not, but for me, it's better than it was pre-finetuning ^^ Thanks again everyone, -off to enjoy his set and maybe rewatch some old movies again :D

Hello rader, everyone

First, many thanks and appreciation for posting and maintaining the spreadsheet. Great job.

I've finally got some time to review it thoroughly.
Below are my inputs, hope you find them useful.

1. RGB from input XYZ calculation, using the matrix specified in F56..H58.
The values specified are of the matrix used for transforming XYZ->RGB of the sRGB color space (not Rec. 709 RGB as specified in the above comment). Hence, caculated RGB values (actual: I56..K65, ideal: J72..L81) are inadequate for RGB Error calculations, and for estimating per-component gammas.
Furthermore, even if the correct Rec709 XYZ->RGB matrix was used, it applies only to HD signals, as SDTV (480i and 576i) use different RGB color spaces (different primaries), hence have different XYZ->RGB matrices (SMPTE RP 145 for 480i and EBU 3213 for 576i).
The user must be able to choose the standard being calibrated - either 480i, 576i or HD - and the matrix values should change accordingly. This assures the calculated RGB values correspond to the correct color space.

2. Gamma estimation
Terminology for the following section:
gamma: exponent _approximation_ (power function approximation: y = x^gamma)
gammaE: gamma used at encoding
gammaD: gamma at decoding. CRTs have intrinsic 2.5 gammaD (due to its built-in relationship betweem voltage input and light output in the electron gun)
transfer function: an explicit formula which defines the correlation between linear-light component and the gamma corrected video signal

When color is encoded (camera side), the Rec. 709 transfer function is used:
V' = 4.5L ; 0 <= L < 0.018
1.099(L^0.45) - 0.099 ; 0.018 <= L <= 1

(lets disregard the linear part for the following discussion)

Due to the scale factor and offset, stating Rec709 has a gammaE of 0.45 is wrong. When approximating this function to a pure power function, you'll get gammaE of about 0.52.

Futhermore, the inverse transformation, L = ((V' + 0.099) / 1.099) ^ 2.2222 simply describes how to recover the scene's linear light RGB values, NOT the RGB values produced by the display's transfer function - which is ofcourse unknown and _should not_ resemble rec709 inverse transformation.
For example, if a CRT is used, then its intrinsic L = V' ^ 2.5 is applied, resulting in an overall (end to end) gamma of 1.3 - suitable for dim environment watching.
I think we should assume display devices try to mimic CRT's intrinsic 2.5 gammaD, hence assume their transfer function is of the type L = (V' + e) ^ gammaD, where 'e' is an error introduced by the zero signal not truely displayed as black.

How this applies to the spreadsheet?
I think all gamma estimation caclulations, which assume display transfer function is similar to the inverse of Rec709 transfer function, are incorrect.
See V56, W56, P72, Q72, R72, S72, T72, U72.
I think that the "+0.099)/1.099" (offset and factor adjustments) should not be used.

GammaD should be estimated using the simple "L=(V'+e)^gammaD" model.
Since you already deduct black level error when normalizing Y values (see P56, formula is deducting Ymin value for normalization purposes) - you are left with even simplier model: L = V' ^ gammaD.

(and thanks to Poynton's excellent "Digital Video and HDTV" ...)

3. % RGB error
Error is calculated as the relative difference between actual RGB values (I56..K65) and the "ideal" RGB values (J72..L81).
However, the "ideal" RGB values are calculated using the _actual_ normalized Y, not the ideal normalized Y (see J72 which refers to D72,E72,F72 which all refer to P56).
Hence, we have RGB errors measured from the reference white point at the luminance level produced by the display (that has non ideal gamma).
An alternative approach might measure the RGB errors from the reference white point with an _ideal_ luminance for the input stimuli.
I'm not 100% sure, but I think that the current implementaion is indeed the desired one, however the issue is debatable...

4. Redundant calculations of ideal X Y Z (D72..F81) and ideal R G B (J72..L81).
Ideal X Y Z are calculated in order to derive ideal RGB values.
However, in any color system, _by definition_, the <1,1,1> RGB triple represents the system's reference white (with Y = 1), and any RGB triple whose components are equal, e.g <a,a,a> , represent the reference white with Y = a.
Hence, ideal R G B values (J72..L81) must always be equal to one another, and their value must always be the same as Y (cell E72).
No need to calculate X and Z, no need for the XYZ->RGB matrix multiplication.

Again, many thanks.
Hope my comments make sense :)

Ok, I've run through about 7 runs and got RGB error under 10%, and De under 4 except for 10% and 100% (it's at 5 for 100%). My color temperature hovers within 200K of 6504K, except at 0-10% irE.

I'm concerned I should be higher overall with the grayscale in order to keep contrast ratio maximized, but maybe this is not a concern as I had to reduce overall contrast by a bit in order to reduce red clipping at 100% IRE. Any input on this?

My main concern is gamma. It is at 2.88. What is the most effective way of getting this down?

Thanks

Hi all,

Ok, I've finally wrapped up the calibration of my Sony GWIII with Radar's spreadsheet, a SpyderTV, and GetGray. I ran it using Theatertek 2.4 using Purevideo process in VMR9 over DVI at 720p.

My results are pretty good, as you can see from the attached images, other than a bit of red runout which I can't seem to eliminate. I got gamma down around 2.3 which is perfect for my viewing environment (fair amount of ambient light).

Questions:

1. With this spreadsheet, is there any way to measure my contrast ratio?

2. I had to increase gamma significantly (UGAM setting from default 0 to 8) to get it into the ideal range of 2.2 to 2.5. Obviously my darks are no longer as black, but I have much more detail in them, but I also now see a lot more grain. Is this normal? Or should I be adjusting something else to compensate for this?

3. Is it safe to assume 1080i over component will have the same settings (HD-PVR, can't run the disk)?

4. I adjust CBOF for 1080i component down to 8 from 31, as per UMR's GWIII recommended settings. Does this sound accurate?

5. Finally, I'm going to post my end result SM settings here for anyone to comment on and possibly provide feedback on if things look accurate or not:

RDRV - 130
GDRV - 129
BDRV - 104
RCUT - 252
GCUT - 242
BCUT - 243
UGAM - 8
AXIS - 2
Contrast (Picture) - 60
Brightness - 39
Colour - 29
Hue - 32

Thanks,

Joe,

I actually personally would prefer the before calibration gamma curve that you posted to the post-calibration one. :) Granted it's too high (you said ~2.88) but it's a smooth, properly-shaped gamma curve for the mostpart. I'm very familiar with the GWIII's as I owned one myself (a 60" XBR950) for close to 3 years so I can attest to mine calibrating similarly to yours.

There are a couple things I see with your calibration that you could probably improve upon. One is the aforementioned gamma curve. :) The other is that the red gamma curve (as you see) climbs faster (i.e., is lower) than green and blue and subsequently begins to hit its limit sooner (as seen from the highest levels not being as bright as they should be going by the gamma curve). I would suggest you back off on the picture setting slightly to get more headroom for red (ending up with something in probably more like the 56-58 range instead of the 60 you're now using) and lower UGAM to more like 4. Then (if needed) lower RGAM separately a notch or two to bring the red curve down to match the green and blue ones. And of course touch up on the grayscale at that point too. :) If you find that you're not clipping on any of the colors at all at that point you could bring UGAM back up a bit to get closer to 2.222 (but right now you look like you're clipping all 3 with pretty bad clipping on red).

Also, you're using an AXIS value of 2 - did you adjust the color decoder settings RYR, RYB, GYR, and GYB separately or are you just currently accepting the severe red push you most likely have as a result? :p

Thanks great advice and i will try it tonight. i"ve switched to axis=1< which i think has ryr and ryb lower than axis=2.

i thought that since all rgb error were within 10% i was ok, but i guess the gamma curve needs to be more smooth, and the clipping is affecting it mostly right now

by backing off on contrast, aren't i severely reducing my contrast ratio?

btw, what did you trade up your gwiii for?

Thanks great advice and i will try it tonight. i"ve switched to axis=1< which i think has ryr and ryb lower than axis=2.

i thought that since all rgb error were within 10% i was ok, but i guess the gamma curve needs to be more smooth, and the clipping is affecting it mostly right now

by backing off on contrast, aren't i severely reducing my contrast ratio?

btw, what did you trade up your gwiii for?Yes you'll probably reduce contrast ratio, but not by all that much given that you're clipping right now. ;) The idea is you want to hit the max level you can without clipping any of the colors. As I recall on my XBR950 that was with a picture of 58. :)

As for what I'm trading up for, it was originally going to be a 70" XBR2, but my order was cancelled on me, at which point I decided to re-evaluate. Now my order (which with any luck I'll be getting tomorrow or Wednesday in the absolute worst case) is a Pearl (projector). :D

Googer,
I adjusted things as you suggested, gamma to 4, contrast to 59 from the above settings, and then some grayscale adjusting, and here are my results. Much better than before and I think I am done unless there is something you or anyone else feels I should make.

I also adjusted AXIS to 0 which is RYB - 24 and RYR 91. Gamma with this calibration is at 2.63, but I can't do anymore about that. There's is a slight red runout at the end, but I can live with that (unless you really feel I should adjust it).

Picture quality looks fantastic!

here also is rgb error

sorry, here it is

That looks quite good now; as you said, there appears to still be very minor clipping on red but it's slight enough it might not be noticeable. You could possibly toy with increasing RGAM to 5 or 6 (and once again have to retouch grayscale :p) and see if you could make it better yet but you would now be getting to the point of diminishing returns. :) At this point you'd almost definitely see much more improvement by properly playing around with the color decoder rather than accepting one of Sony's presets. ;)

What should I be looking at when adjusting the color decoder? Should I be looking at the color/tint on DVE or GetGray through the red filter? What am I looking for? Or should I assume AXIS 0 is best?

You're looking to move the color secondaries (yellow, magenta, and cyan) closer to their reference points. What you should aim for is to have them form a straight line with the complementary primary color (i.e., blue for yellow, green for magenta, and red for cyan) that passes straight through the D65 point, though I don't know that I've ever seen if it's considered more optimal to put a secondary color closer to the reference point or if it's better to maintain this 'straight-line' approach when one has to make a decision as to which one to go for. ;) Optimal would be to move the primaries to their reference points as well but that's unfortunately not possible. :p

So in Radar's spreadsheet, when I select GetGray tab and do the xyY values, and have gotten that all naileddown, is the CIE chart on the HD907 tab my CIE chart, or for another evaluation and thus not tied to my calibration.

If so, then I guess I can use that in your explanation, otherwise, when I'm looking through filters at GetGray or DVE patterns, I can't really work to "line up color points".


Thanks,

When sending an HDMI signal from an upscaling DVD player, through an HDMI-switching equipped AV receiver, and then out to the Sony GWIII's DVI-input, is is better to set the receiver and player to output the video in RGB or YCbCr format?
Also, what is the best upscaled resolution to send for the KF50WE610?

Thanks.

I think that one of the most important reasons for calibrating gamma in a TV is to make each luma step have nearly equal perceived weight. So instead of trying to calibrate for a specific gamma we could try to achieve a uniform lightness step size. To do that we could divide the range of lightness from the measured black point to the measured white point into uniform lightness steps and use the corresponding intensity levels as calibration targets. To see how uniform we should expect the lightness steps to be I wrote a Matlab script to plot the perceived lightness steps for a theoretical monitor driven with 5% luma steps. I noticed that for a TV with good black levels in a dark room where the achieved CR might be 5000:1 a gamma of 2.5 yielded reasonably uniform perceived lightness steps. In a different situation with an achieved CR of only 50:1 like might happen in a bright room a gamma of 2.22 yielded fairly uniform lightness steps. These plots are included below after the Matlab code. So, would calibrating for uniform lightness steps be a good idea?

Matlab code:
lightness= inline('(116*x.^(1/3)-16).*(x>.008856) + 903.3*x.*(x<=.008856)','x');
intensity= inline('((x+.099)/1.099).^g .*(x>.081) + (.18/1.099).^g/.081*x.*(x<=.081)','x','g');
y= 0:0.05:1;
gamma= 2.22;
I= intensity(y,gamma);
CR= 50;
I0= 1/(CR-1);
Itotal= (I+I0)/(1+I0);
steplightness= diff(lightness(Itotal));
ymidstep= mean([y(1:end-1); y(2:end)]);
plot(ymidstep,steplightness/mean(steplightness));
grid;
title(['Lightness Step Size: CR= ' num2str(CR), ', Gamma= ',num2str(gamma)]);
maxstepoffset= max(abs(steplightness/mean(steplightness)-1))

Joe, Googer is good at color decoder settings....I forgot about this post....G.B.

I use my Dell 24" LCD monitor hooked to a Scientific Atlanta Explorer 3250HD cable box to watch tv, I downloaded the spread sheet last night and hooked my Samsung DVD player to the monitor and took readings (Using Spyder2Pro with the Filter on).

IRE x y Y
Black 0.289 0.257 0.831
10 0.27 0.196 1.109
20 0.275 0.248 10.577
30 0.278 0.268 38.448
40 0.28 0.279 84.622
50 0.291 0.295 150.262
60 0.297 0.306 220.835
70 0.302 0.314 248.098
80 0.288 0.301 270.456
90 0.307 0.337 363.795
100 0.325 0.342 392.212


The only controls for this input I have are:

Brightness 52
Contrast 63
Hue / Tint 52
Saturation 92

Settings made with the Avia Disk and filters for basic calibration, there is no way to adjust RBG Any suggestions? I plan to test this method out on my 27" CRT TV in Living room this weekend.

Edward

I found a minor spreadsheet error and I also have a question.


First the error: On the "HD Color" tab, in the Delta E plot (top right) the magenta bar is plotting the Cyan data.



Now for my question. I'm discovering that the green primary on my set (Pioneer 6070) is off from the standard as measured with the Spyder. Does this impact the validity of the math used to calculate the red,green and blue errors in the color temperature (i.e. the AVIA tab) ?

Does anyone have the corrected version of the Rader spreadsheet?

Hi

i have a Konica Monolta CA-210 at work can i use this with your spread sheet, it uses x, y, Lv is Lv just the same as Y.

thank you

Why isn't this very useful spreadsheet and info not a sticky?? :eek:

Why isn't this very useful spreadsheet and info not a sticky?? :eek:
The forum moved on to using HCFR as the freeware solution. We, obviously, have a low-cost alternative, and since both programs talk directly to the meters, a manual spreadsheet just isn't as useful as it once was (CalMAN originally stood for Calibrate Manually).

Bill

The forum moved on to using HCFR as the freeware solution. We, obviously, have a low-cost alternative, and since both programs talk directly to the meters, a manual spreadsheet just isn't as useful as it once was (CalMAN originally stood for Calibrate Manually).

Bill

I remember the hours of that manual labor!