or Connect
AVS › AVS Forum › Display Devices › Display Calibration › Guide: GREYSCALE CALIBRATION FOR DUMMIES
New Posts  All Forums:Forum Nav:

Guide: GREYSCALE CALIBRATION FOR DUMMIES

post #1 of 258
Thread Starter 
Hi everyone!

I'd like to announce a new extensive guide I've put together.



Link: GREYSCALE & COLOUR CALIBRATION FOR DUMMIES »

(Update: It's no longer just greyscale calibration as I've added some new sections on colour decoders, primaries/secondaries, etc).

Over 250 hours of research and writing have gone into this guide.

This guide came about as the do-it-yourself (DIY) crowd has been asking more and more about greyscale and colour calibration over the years. With reliable colorimeters now under $150 USD and excellent free software like ColorHCFR available, it's a no-brainer that all DIY enthusiasts have some sort of colorimeter in their toolbox. If for no other reason than to better appreciate the complexities of colour calibration when they speak to a professional calibrator.

Countless number of calibration guides have been published prior to this one. Some of them quite good. The problem I found is that most assume that the reader already has the required equipment and knows exactly how to set it up properly. Most guides also assume that the reader has a good understanding of terms like D65, stimulus, CIE, etc. Some even provide links to highly technical documents as "required reading". Yes, many of these documents are very informative, but not everyone wants to earn a doctorate in colorimetry so that they can set their greyscale properly.

My guide takes a step backwards and makes the assumption that the reader has absolutely no knowledge of colour calibration. In fact, this guide assumes that the reader doesn't even *know* what "greyscale calibration" is! I explain what it is, why it's important, list the tools needed, where to get them, and walk you through the process from start to finish.

I hope you find it useful.

Comments and feedback are appreciated. I'm still tweaking portions of it as questions arise.

Kal
post #2 of 258
Good Morning Kal,

I can't thank you enough for putting this together, it has been a big big big help.

tomorrow I should be getting my i1 DisplayLT meter and am looking forward to redoing my calibration, I have been reading the site over again since I know you've made changes and updates since I last went thru it.

I was curious if you could talk to the Luminance graph and is there away to explain what the best course of action is for someone getting readings like this (see attached)

does that mean that my contrast is set to high and I need to lower it and decrease my brightness to achieve the right (or as close to right) readings?

or do I need to do the opposite, increase the contrast
LL
post #3 of 258
Thread Starter 
Hi!

Wow - interesting graph. The luminance is way too high at every single point.
What's your display? What's your signal chain? Do you have any way of adjusting gamma? (There's currently too much of a boost - ie: the gamma value is too low at every single point).

Post your entire ColorHCFR file if you like.

If you think of your yellow line as a string, adjusting contrast will simply have the effect of pushing or pulling the string up or down. It shouldn't affect the curve too much unless you're pushing the display into blooming.

Kal
post #4 of 258
I have a Sony KDS 50A3000, I calibrated during the day because that's when we watch most of our TV (at least for the living room) I made sure I had no external light on or pointing at the display.

I also used the spyder II to calibrate and I'm wondering if I got one that wasn't very accurate (that's why I can't wait for the i1 to show up)

as you can see between 30 and 90 I get the most consistency with the RGB's but I wanted to really work on getting my Luminance more correct.

I've received some good information from thomasl and alluringreality(<- think that's how you spell his username) in the main thread for HCFR, when my i1 shows up I'm going to take some night time readings with no extra light to see how much the difference is.

 

Color_After_Cinema_2_attempt.zip 5.5546875k . file
post #5 of 258
You have manage to bring greyscale calibration to the masses... Thank you very much... I came across your guide a week ago and immediately ordered an eye-one. Three days later I got it in, I downloaded the ColorHCFR software and loaded onto my lap-top, got out the tri-pod and the DVE disc and within about an hour had my Z4 calibrated and learn a lot about my set-up in the process. I have my new Sony Black Pearl arriving this week and can't wait to calibrate it too. Your guide is targeted precisely at folks like me and I'm very glad you took that approach of assuming the reader doesn't know the important of greyscale calibration nor any of the 'jargon' use in talking about it. I can't express my appreciation enough, however I think I will try to by dropping down a donation over there.
post #6 of 258
Thread Starter 
Hi Creatine64: I'd certainly be interested in hearing how the Eye-One compares to your Spyder2. Some Spyder2's are ok, but not all. Mine's so-so as compared to my Eye-one.

Monomer: Thanks for the compliments! I started researching this myself and saw all the confusion that I figured I should try and help out a bit... The information's all out there of course, but it's in 1000 different posts. This is my attempt to compile all the basic information in one spot.

Kal
post #7 of 258
Thank you very much for this guide. I can't tell you how much it helped. I did not know my projector could look that good. I just got done calibrating my grayscale it with my i1 Display LT. My HC3000 looks amazing. I was able to get a really good result with my PS3 connected via HDMI and a pretty decent result with my HD-A3 connected via component. It is amazing how well it worked. I enjoyed calibrating the display much more than I would have enjoyed hiring someone to do it for me.
post #8 of 258
Quote:
Originally Posted by Jedirun View Post

I enjoyed calibrating the display much more than I would have enjoyed hiring someone to do it for me.

Don't forgot about your other Displays..
post #9 of 258
I currently have a 1080P DLP LED HDTV (Samsung HL61A750,16:9) and am also looking into getting a 1080P LCD HDTV (Samsung LN46A650,16:9) and would like to know the following:

1. Since these are 1080P HDTVs would the GetGray (NTSC version) be a more effective calibration disc than the DVE HD Basic calibration disc? Read that GetGray was easier to use and navigate.
2. Would I still get a good quality calibration with no further equipment used but the disc and my eyesight? Would it be THAT much better with HCFR software and a Eye-One Display LT kit?
3. I have used the AVCHD (HD 709) free AVS Calibration disc and have seen a good improvement over default settings. Will the GetGray still be an improvement over that or should I wait for a possible HD version for GetGray?
I will be using a PS3 (bluray) for any calibration disc.
Thanks in advance to you calibration experts!
post #10 of 258
Quote:
Originally Posted by alvin4520 View Post

I currently have a 1080P DLP LED HDTV (Samsung HL61A750,16:9) and am also looking into getting a 1080P LCD HDTV (Samsung LN46A650,16:9) and would like to know the following:

1. Since these are 1080P HDTVs would the GetGray (NTSC version) be a more effective calibration disc than the DVE HD Basic calibration disc? Read that GetGray was easier to use and navigate.
2. Would I still get a good quality calibration with no further equipment used but the disc and my eyesight? Would it be THAT much better with HCFR software and a Eye-One Display LT kit?
3. I have used the AVCHD (HD 709) free AVS Calibration disc and have seen a good improvement over default settings. Will the GetGray still be an improvement over that or should I wait for a possible HD version for GetGray?
I will be using a PS3 (bluray) for any calibration disc.
Thanks in advance to you calibration experts!

First off I am certainly not a calibration expert. I have calibrated only 1 display, but here is my experience.

1. While GetGray is clearly a superior calibration disk. On both of my sources, PS3 and HD-A3 the output for black level and white level are different when using a SD DVD as compared to an HD DVD or Blu-Ray. The PS3 was much closer for the two sources, it is almost not noticable, but it was measurable with the i1 Display LT. The color calibration did not significantly change. On my HD-A3 the difference between HD and SD sources is significant. If the display is properly calibrated for HD it looks terrible for SD and vice versa. I guess that is why there are multiple memories on my projector.

I calibrated the HD-A3 with HD Basics and the PS3 with both HD Basics and GetGray. GetGray is just set up better and easier to use, but to make sure everything was optimized I wanted HD sources to ensure the levels were correct when watching Blu-Ray and HD DVD. I calibrated the PS3 for SD DVD, because it does a much better job with SD than the HD-A3.

2. You will get a good quality calibration with just your eyesight. It will certainly be improved over the factory settings. However, I noticed a significant difference after using the i1 Display LT and HCFR. Take the plunge and buy the colorimeter. It is worth it.

3. I have not used the AVCHD (HD 709) so I can not comment on it.
post #11 of 258
Quote:
Originally Posted by turbe View Post

Don't forgot about your other Displays..

You are right. I need to get those taken care of.
post #12 of 258
Thread Starter 
Quote:
Originally Posted by Jedirun View Post

Thank you very much for this guide. I can't tell you how much it helped. I did not know my projector could look that good. I just got done calibrating my grayscale it with my i1 Display LT. My HC3000 looks amazing. I was able to get a really good result with my PS3 connected via HDMI and a pretty decent result with my HD-A3 connected via component. It is amazing how well it worked. I enjoyed calibrating the display much more than I would have enjoyed hiring someone to do it for me.

Glad you enjoyed the guide!

Quote:
Originally Posted by alvin4520 View Post

1. Since these are 1080P HDTVs would the GetGray (NTSC version) be a more effective calibration disc than the DVE HD Basic calibration disc? Read that GetGray was easier to use and navigate.

By all means use it. I only suggest DVE since it's one that's the most accessible and easy to find for people. I actually use AVSHD709 myself as the test patterns are nicely set up to HCFR and it's quick to navigate. But I don't have it in the guide (yet) since (a) it's HD only, and (b) you have to burn it yourself which not everyone knows how to do, and (c) it's not done yet so the menu names/etc may change in the final version. I really want to make it simple as possible. I intend to add some extra text in the future listing other test discs that people can use that will give you the same results.

FWIW, I do own DVE:HD basics too of course. It's worth it just for the first hour or two of intro/historical stuff. Really interesting. (Well, at least to me it was).

Quote:


2. Would I still get a good quality calibration with no further equipment used but the disc and my eyesight? Would it be THAT much better with HCFR software and a Eye-One Display LT kit?

Someone who has a lot of experience and knows what they're looking for can do reasonably well by eye. Not really close, but 'reasonable'. The problem is, you usually need a lot of experience with a colorimeter before you get to that point. So if you already have a colorimeter, why not keep using it? It's a bit of a catch-22.

Quote:


3. I have used the AVCHD (HD 709) free AVS Calibration disc and have seen a good improvement over default settings. Will the GetGray still be an improvement over that or should I wait for a possible HD version for GetGray? I will be using a PS3 (bluray) for any calibration disc.

I don't know what other features GetGrey has as I've never used it, but AVSHD709 has all you need to use my guide so the results should be the same.

Kal
post #13 of 258
alvin4520 -- Concerning your "Point #3", right now there are no plans for a HD version of the GetGray disc (AFIK), since the BD authoring tools are too expensive (this has been mentioned, ad nausium, in the GetGrey thread).

As Jedirun mentioned, the GetGray disc works fine in a PS3, since the grayscale is not effected by the HD (Rec 709) vs SD (Rec 601) color coding (it's the same grayscale). However, for complete HD calibration the AVS HD 709 (as a minimum) should be used to verify that the color calibration is correct for HD discs.

kal -- Thank you for your efforts. I haven't read your entire "tome", but it looks like you may have pushed me over the edge in getting a colorimeter. I've been doing my own eyeball PJ calibrations since the original release of Joe Kane's original "A Video Standard" on Laserdisc in 1986. I currently use the GetGray disc, and I'm planing on getting a 1080p PJ and a BD player sometime this year.
post #14 of 258
Kal,

Appreciate your hard work putting the guide together. Like Claus, this document definitely pushed me over the edge in getting a colorimeter.

Now a question: in the guide it is recommended that HCFR is set with the color space definition that matches the calibration test pattern source. This sets the reference standard within HCFR for the color gamut only and has nothing to do with the greyscale calibration itself, since D65 is the same for all standards.

However, in all my reading, for many TVs, the primaries cannot be altered without a full CMS. So on an HDTV, when displaying a red primary, it should be compared to the HD 709 reference point. Hence, the HCFR setting for color space should correspond to the display, and not the source (unless you're calibrating for individual sources with a CMS).

Of course, none of this matters in a greyscale calibration, but would affect a primary measurement/calibration.

If I have this wrong, someone please correct me.
post #15 of 258
Thread Starter 
Quote:
Originally Posted by tsanga View Post

Appreciate your hard work putting the guide together. Like Claus, this document definitely pushed me over the edge in getting a colorimeter.

I starting to think I should have bought stock in the companies making these colorimeters.

Quote:


Now a question: in the guide it is recommended that HCFR is set with the color space definition that matches the calibration test pattern source. This sets the reference standard within HCFR for the color gamut only and has nothing to do with the greyscale calibration itself, since D65 is the same for all standards.

Correct. That's my understanding as well.

Quote:


However, in all my reading, for many TVs, the primaries cannot be altered without a full CMS.

Yup. Very true. It's something I do mention the the primaries section I'm about 1/2 done writing up now. The lack of "things to do" is what's taking it so long to write.

Quote:


So on an HDTV, when displaying a red primary, it should be compared to the HD 709 reference point. Hence, the HCFR setting for color space should correspond to the display, and not the source (unless you're calibrating for individual sources with a CMS).

Not sure I follow. What do you mean by "the HCFR setting for color space should correspond to the display and not the source"? If our source is Rec709 (HD) then we'll want to know how well it does at displaying the extended Rec709 gamut by measuring the primaries.

I'm probably just not understanding...

Kal
post #16 of 258
Kal,

Specifically, I'm referring to the case where a SD DVD is used to calibrate a HD display. This could be the case where the GetGray DVD (or the SD variants of Avia or DVE) is used in a SD DVD player to calibrate the HDTV.

In the guide:
Quote:


If you are using a Blu-ray or HD DVD test disc, set the "Color Space - Standard" option to HDTV - REC 709.
If you are using a Standard DVD test disc that is in NTSC format, set the Color Space - Standard option to SDTV - REC 601 (NTSC).
If you are using a Standard DVD test disc that is in PAL or SECAM format, set the Color Space - Standard option to PAL/SECAM.

However, since the x-y location of primaries cannot be altered without CMS, the HDTV will show primaries capable of and close to those defined by 709. This will be true when you feed the TV primary colors, regardless if the source is pure R, G, or B encoded in the SD 601 or HD 709 color space (because digital RGB is the same). So if the TV is fed only red, the display will show 100% saturated red, regardless of whether the red comes from a SD or HD source.

Another way to look at it: if the HD display is fed red from a SD source, it doesn't display red as defined in the SD gamut, but tries to display red at the HD gamut location, because in RGB, red is defined with the same digital level.

Therefore, HCFR should be set to SD 601 if trying to measure primaries on a SD display, and set to HD 709 if trying to measure primaries on a HD display, regardless of source (when primaries cannot be changed on that particular display).

Again, if my understand is incorrect, please jump in.
post #17 of 258
Quote:
Originally Posted by kal View Post

If our source is Rec709 (HD) then we'll want to know how well it does at displaying the extended Rec709 gamut by measuring the primaries.

There's some talk on here that HD material might still be mastered using SMPTE-C primaries. If that's the case, then in an idealized setup both SD and HD sources would be calibrated to those primaries. At the very least, I found http://www.avsforum.com/avs-vb/showt...2#post11877342 informative in trying to sort out some of my misconceptions.
post #18 of 258
I also read that thread. But regardless of how HD material was mastered....

If I understand Chris Wiggles correctly, then:
- The primary color locations for a display are fixed and native to the display, unless it has an advanced CMS.
- Regardless of whether you're feeding the TV 100% saturated red from a SD or HD source, the display will show the same digital R level, provided the color space transforms are applied properly, i.e. as long as the TV is anticipating the same color space as the DVD (SD or HD) output. Therefore, your display will show the same red regardless of which source it came from, despite differences in the color gamut definition.
- This means when calibrating a HDTV, the target should be those locations defined by Rec. 709. Then HCFR should NOT be set to match the source even if that source is a SD DVD (e.g. GetGray DVD).
- If a display has the ability to move primary locations, then one could calibrate one input per the SMPTE-C definitions, and another per Rec. 709. Then HCFR could be set to use either 601 or 709 as the target for each respective calibration.

But as I said before, none of this matters for grey scale. All this is about is setting a target for color calibration, and what I'm trying to say is the target should be set independent of the source, and more to what one's trying to achieve.
post #19 of 258
Thread Starter 
Quote:
Originally Posted by tsanga View Post

Therefore, HCFR should be set to SD 601 if trying to measure primaries on a SD display, and set to HD 709 if trying to measure primaries on a HD display, regardless of source (when primaries cannot be changed on that particular display).

Ah - I see your point. Makes sense. I would do as you state. I've never wanted to calibrate anything that only did 480i (SD) so I've only ever done HD (Rec709).

The others are correct in that it doesn't matter for greyscale, and this is what I mention in my guide.

Kal
post #20 of 258
Quote:
Originally Posted by tsanga View Post

regardless of how HD material was mastered....

when calibrating a HDTV, the target should be those locations defined by Rec. 709.

I'll have to generally disagree with the portion quoted. If the source is HD and mastered with SMPTE-C primaries then to calibrate you would ideally set the display to those xyY values and not the ones defined by Rec 709. Unless the material is mastered with 709 primaries, then the ideal would be to calibrate SD and HD to SMPTE-C primaries.

From a practical aspect this is outside the capabilities of most displays because the vast majority don't have a CMS. In that regard it's somewhat a moot point because you're limited on what can be changed with the TV's controls. I do select 709 for my HD display, but it's mostly because the display's primary xy points just line up with that standard and the controls available for adjusting colors are limited. Just because I select the 709 primaries with my display though, it's not because that's necessarily correct in general. Without a means to alter primary xy locations, then generally I would agree to simply choose whichever standard comes closest to the display's primaries.
post #21 of 258
a-r, agreed.
post #22 of 258
When setting the gray scale calibration, you don’t talk about how to set the Color and Tint controls of the TV at all. You go right into the RGB High and Low tweaking. Does this mean my Color and Tint controls should be at there default and just use the RGB High a Low controls to get to the D65 target?
post #23 of 258
Color controls (color and tint) are generally independant from grayscale controls (RGB high and low). It's not a bad idea to set the color controls half-way close before doing grayscale, but it doesn't necessarily have to be done that way on every display. The current guide doesn't at all address color controls.
post #24 of 258
Thread Starter 
Hi! Colour and tint will be added shortly to the procedure, making this guide a "Colour Calibration for Dummies" guide instead of only a "Greyscale Calibration for Dummies" guide.

In the meantime seen Tom Huffman's excellent guide here: http://www.avsforum.com/avs-vb/showthread.php?t=852536

He doesn't show you the step by step details but most people should be able to figure it out. If not, wait for my guide.

Kal
post #25 of 258
so leave the color and tint and default and just work with RGB controls?

Quote:
Originally Posted by alluringreality View Post

Color controls (color and tint) are generally independant from grayscale controls (RGB high and low). It's not a bad idea to set the color controls half-way close before doing grayscale, but it doesn't necessarily have to be done that way on every display. The current guide doesn't at all address color controls.
post #26 of 258
tsanga & others -- Regarding your question on Rec 601 vs Rec 709 color space, it all depends on what your source is, what DVD player you are using and what resolution you are sending to your display.

Most of the good upconverting players (SD DVD, BD players, or HD-DVD players set to output a HD signal) will correctly convert (re-matrix) the SD (Rec 601) source to the Rec 709 color space using the HDMI output. This was verified by more than one AVS member comparing the GetGray SD disc to the AVS HD 709 disc, for example, on a BD player (I can't find the threads right now).

The only place where it makes any difference is in calibrating an SD source vs an HD source, and those are not really in question - the color settings are supposed to be different.

PS -- Since AVS HD 709 is free (thanks alluringreality), this is an easy comparison to make (comparing to any SD calibration disc, if you have one).
post #27 of 258
Claus,

What about a SD source (GetGray), in a NON-upconverting DVD player, used to calibrated a HD display?

As I mentioned, my understanding is that the location of the primaries on the TV are fixed. So when you use that SD source to tell the TV to display, for example, 100% saturated red, the TV expects SD colorspace over the 480i signal, and translates it to full digital R, and displays its primary color red. So what ends up being shown is a red capable of meeting the Rec 709 spec, despite coming from a SD source.

Is that correct?
post #28 of 258
Thread Starter 
Update:

I've now added Part 8: Advanced Colour Management (Primaries & Secondaries) to the guide which makes the guide now complete.

If anyone has any comments or (more importantly) sees any mistakes please let me know! Thanks!

Kal
post #29 of 258
This is a great guide and thanks for doing this!
post #30 of 258
Incredible!!! Thanks so much for all the efforts.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Display Calibration
AVS › AVS Forum › Display Devices › Display Calibration › Guide: GREYSCALE CALIBRATION FOR DUMMIES