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The Official ChromaPure thread - Page 123

post #3661 of 5355
Quote:
Originally Posted by hungro View Post

Using the gamma pattern from the GCD disk, I calibrate the gamma to target of 2.22 in the gamma module it looks really linear and fairly flat when I am done using the 10 pt controls. I then switch to a Greyscale pattern and take a full grey scale run the gamma in the different % of white range is lower then 2.22 from say 50% white to 90% white. Why does the gamma appear much more linear using the real time gamma module and then when you take a full greyscale reading it is different? What could be making the difference between the two patterns. My avg gamma ends up being around 2.18 . Is there anything wrong with how the gamma looks? perhaps I am being too critical , any thoughts?
Several things going on here.
  • Your concern seems to be about discrepancies between the Grayscale module and the Gamma module, but the documentation provided concerns pre/post-calibration data. I would expect values to change between the pre and post-calibration states, and sure enough they changed substantially. Look at the difference in peak output: 95 vs. 108
  • Nonetheless, although there are small differences at individual levels, the ave gamma response in pre/post are about the same: 2.19 vs. 2.18.
  • Finally, I ran the pre-calibration run and then took a full run in the Gamma module. They measured the same.







Take a pre-calibration run and then a gamma run. See if they are different. I don't see it.
post #3662 of 5355
Quote:
Originally Posted by hungro View Post

I think the idea is see 17 flash not 16. 16 is refrence black it should not be visible at all be invisible smile.gif 17 just barely visible.

So what would 17 be equal to in a near black % pattern since I have no luck with the flashing bars!?

bob
post #3663 of 5355
Quote:
Originally Posted by spongebob View Post

So what would 17 be equal to in a near black % pattern since I have no luck with the flashing bars!?
bob
Hello, 17 is 1% above black, perhaps Tom would be able to better explain smile.gif but I'll try first . I am not sure but I think if you set your black level where 1% above black window pattern is just barely visible you should be golden. If you go one click on the brightness control lower and the window disappers then you are clipping 17 as well which would be considered too low. I also don't want to lead you in the wrong direction if this method doesn't work or doesn't give accurate results. Can the experienced chime in ?
post #3664 of 5355
Quote:
Originally Posted by hungro View Post

Hello, 17 is 1% above black, perhaps Tom would be able to better explain smile.gif but I'll try first . I am not sure but I think if you set your black level where 1% above black window pattern is just barely visible you should be golden. If you go one click on the brightness control lower and the window disappers then you are clipping 17 as well which would be considered too low. I also don't want to lead you in the wrong direction if this method doesn't work or doesn't give accurate results. Can the experienced chime in ?
1% above black is more like 18.

8-bit video spans 16-235. That is 219 code values, so there is not a one-to-one relationship between a code value and percent values. 17 is one code value above black, so close in fact that it may be hard to visually distinguish from 16. If you can see 18 but cannot see bars below 16, then that's good. If brightness is set too high, you'll be able to see bars below 16. If it is set too low, 18 will fade into the background and become invisible.
post #3665 of 5355
What setting do you use with an LCD display, that allows you to see a flashing 17 if viewed at an angle but not if viewed straight on?
post #3666 of 5355
You shouldn't calibrate an LCD by viewing it off axis.
post #3667 of 5355
Quote:
Originally Posted by TomHuffman View Post

1% above black is more like 18.
8-bit video spans 16-235. That is 219 code values, so there is not a one-to-one relationship between a code value and percent values. 17 is one code value above black, so close in fact that it may be hard to visually distinguish from 16. If you can see 18 but cannot see bars below 16, then that's good. If brightness is set too high, you'll be able to see bars below 16. If it is set too low, 18 will fade into the background and become invisible.

I understand what you are saying. What I don't is this, what should 17 appear like? i usually set it to where it's barely visible hard to distinguish with my nose right up to the screen. Is this correct?
post #3668 of 5355
Quote:
Originally Posted by hungro View Post

I understand what you are saying. What I don't is this, what should 17 appear like? i usually set it to where it's barely visible hard to distinguish with my nose right up to the screen. Is this correct?
Yes, but what I suggested is that focusing on 18 would probably be easier.
post #3669 of 5355
Quote:
Originally Posted by hungro View Post

I understand what you are saying. What I don't is this, what should 17 appear like? i usually set it to where it's barely visible hard to distinguish with my nose right up to the screen. Is this correct?

If 17 is just a few green pixels firing sporadically, it would be better as Tom said to just focus on 18. Many plasma owners (sorry, didn't read what display you have, so may not apply) crush video level 17 and use 18 to set their near black level when using the AVS disc.
post #3670 of 5355
Any holiday specials going on for Chromapure and hardware?
post #3671 of 5355
I do have a feature request for Chromapure, probably has been requested already. I would like to see a numerical gamma value when using the White Balance module. No graphs needed. I do most of my greyscale work in that module, as its bit easier to select whatever setting or value required, useful for spot readings and/or quick checks. With the other modules, you cannot take continuous readings or there a prerequisites that must be set/selected; not to criticize those as they work just fine. As for target Y, it could be a value entered manually in some small box or some button like "press to set target peak luminance", as there's plenty of screen real estate where something like that could be incorporated.
post #3672 of 5355
I used to use the WB module but now I much prefer the Gamma module for adjusting gamma and greyscale at the same time.

I've requested that the Gamma value be included in the Raw Data window (in the Gamma module) to make it more visible (it's there in the chart but having it in the Raw Data window right next to the RGB data would be a nice touch).
post #3673 of 5355
Hello,

I have an Epson 6010, Chromapure Standard and a D3 Pro.

Below is my calibration report, I think it looks ok but a couple things have me concerned and Im at a loss on how to move forward.

When I took my initial Greyscale the red was down a ton through the range, in order to fix it and get the results I did, I had to raise the red gain to 20. After I did that I went back to the contrast setting screen and could see a pinkish tone to the bars that were flashing. In order to get those to go away I had to drop my contrast to -18, which again seems really low...

What you see below is my calibration after setting the gain on Red so high and the contrast so low...Any direction you can give?

post #3674 of 5355
Quote:
Originally Posted by kaotikr1 View Post

Hello,
I have an Epson 6010, Chromapure Standard and a D3 Pro.
Below is my calibration report, I think it looks ok but a couple things have me concerned and Im at a loss on how to move forward.
When I took my initial Greyscale the red was down a ton through the range, in order to fix it and get the results I did, I had to raise the red gain to 20. After I did that I went back to the contrast setting screen and could see a pinkish tone to the bars that were flashing. In order to get those to go away I had to drop my contrast to -18, which again seems really low...
What you see below is my calibration after setting the gain on Red so high and the contrast so low...Any direction you can give?
I would not be too concerned about the pinkish result on the contrast test pattern unless you also see it with a 100% test pattern. You might also try leaving contrast alone and lowering blue and green instead of raising red.
post #3675 of 5355
Toms, Thanks for the info on the USB to serial adapter with the FTDI chipset. I picked one up from Amazon and used it with the DVDO iScan Duo Control Panel program. So I should be all set when I get Chromapure to connect with my DUO. After flip flopping for over a year about getting Chromapure and the X-Rite Display 3 PRO Colorimeter , I will finally be pulling the trigger on it soon since I have a new DLP set on the way.Once an order is placed is it shipped out within a day or two? I live in the DC area so I figure the shipping time should be minimal since you are close.
post #3676 of 5355
Quote:
Originally Posted by TomHuffman View Post

I would not be too concerned about the pinkish result on the contrast test pattern unless you also see it with a 100% test pattern. You might also try leaving contrast alone and lowering blue and green instead of raising red.

Thanks Tom.

What's also the best way to adjust gamma at each IRE? Do I use the custom gamma on my Epson, which is kind of hard to understand, or do I adjust RGB High End and Low End? I think I have the rest down but I just seem to be lost on what to do when it comes to making adjustments to gamma....

It seems like if I adjust RGB for Gamma, it will adjust my grey-scale....

I have used the Gamma module in Chromapure, but I notice that is goes off of the 100 IRE window so even if you go into that module and then take your measurements, if you start to make changes, they really don't do any good because when you remeasure your 100 IRE has changed, thus negating your efforts...

Just thinking out loud....
post #3677 of 5355
Quote:
Originally Posted by kaotikr1 View Post

Thanks Tom.
What's also the best way to adjust gamma at each IRE? Do I use the custom gamma on my Epson, which is kind of hard to understand, or do I adjust RGB High End and Low End? I think I have the rest down but I just seem to be lost on what to do when it comes to making adjustments to gamma....
It seems like if I adjust RGB for Gamma, it will adjust my grey-scale....
I have used the Gamma module in Chromapure, but I notice that is goes off of the 100 IRE window so even if you go into that module and then take your measurements, if you start to make changes, they really don't do any good because when you remeasure your 100 IRE has changed, thus negating your efforts...
Just thinking out loud....
Gamma is always calculated from the 100% reading. That's unavoidable. After making any changes that would affect peak outout, you always have to remeasure gamma.

I recall calibrating an Epson 5010, and I couldn't figure out how the custom gamma tool worked. In any case, I used the 2.2 gamma preset, which was pretty good.

http://www.displaycalibrationonline.com/reviews_epson5010.asp
post #3678 of 5355
Appreciate the support, I got a really good result tonight after taking your advice. Really enjoy how easy the tool makes it once you get used to it.
post #3679 of 5355
Quote:
Originally Posted by Geof View Post

I used to use the WB module but now I much prefer the Gamma module for adjusting gamma and greyscale at the same time.
I've requested that the Gamma value be included in the Raw Data window (in the Gamma module) to make it more visible (it's there in the chart but having it in the Raw Data window right next to the RGB data would be a nice touch).

The Gamma Screen has my vote as well.

Absolutely no problem doing Gamma and x,y coordinates together to achieve correct balance.

The 'uncluttered' lines of the 'Raw Data' are perhaps something Tom would like to keep but maybe somewhere along the line perhaps this view could have a drop down menu that allows 'additions' to get a perhaps more useful view for certain adjustments?

The drop down menu system works very well when selecting my 75% Rec 709 patterns and x,y rather than hsl so it is not too radical a suggestion.
post #3680 of 5355
Quote:
Originally Posted by PE06MCG View Post

The Gamma Screen has my vote as well.
Absolutely no problem doing Gamma and x,y coordinates together to achieve correct balance.
The 'uncluttered' lines of the 'Raw Data' are perhaps something Tom would like to keep but maybe somewhere along the line perhaps this view could have a drop down menu that allows 'additions' to get a perhaps more useful view for certain adjustments?
The drop down menu system works very well when selecting my 75% Rec 709 patterns and x,y rather than hsl so it is not too radical a suggestion.
I'm not sure I follow. There is a nice spot to add a gamma value - in the blank spot just above the CCT reading in the 2nd column.



Edited by Geof - 12/22/12 at 7:01am
post #3681 of 5355
Quote:
Originally Posted by Geof View Post

I'm not sure I follow. There is a nice spot to add a gamma value - in the blank spot just above the CCT reading in the 2nd column.

Sorry if it was confusing.

I agree that your suggested placement for the gamma would be ideal with a minimum of extra data on the Raw Data view.
I was in fact agreeing with you.

Regarding Drop Down Menus,
CMS views use them successfully to enable choice of say gamut patterns (say 75% rec709) and measuring characteristics (say hsl or xyY).
I am suggesting that some views could benefit by further use of a Drop Down Menu thus allowing more personal choice for the excellent suggestions that Forum Members bring forward.

There would not necessarily be more on the view just a choice of what to show, Tom would still decide where it goes on that view, we would decide what we like to see during our obviously different preferred real time calibration views.

Really just a suggestion about how to handle suggestions if that makes sense.

Hopefully Tom will not see this as impertinence and perhaps there are extremely good technical reasons why this cannot easily be done, but that's my explanation of my previous post.
post #3682 of 5355
Ah, gotcha, thanks for "unconfusing" me....cool.gif
post #3683 of 5355
Quote:
Originally Posted by Geof View Post

I used to use the WB module but now I much prefer the Gamma module for adjusting gamma and greyscale at the same time.
I've requested that the Gamma value be included in the Raw Data window (in the Gamma module) to make it more visible (it's there in the chart but having it in the Raw Data window right next to the RGB data would be a nice touch).

My issue with the Gamma module (and this only pertains to what I talked about; the module itself is just fine) is that I would have to go through a complete greyscale run before I can select individual greyscale values (including having to check boxes at 5% intervals). It makes it a little more time-consuming to do a spot-check on specific values. In addition - and this may only apply to a few displays like my own - my 100% White Y value inflates a bit (ex. 103.5 cd/m2) before it stabilizes at a certain value (100 cd/m2) for ~90 seconds, and then the ABL kicks in and the luminance begins to drop. That's why I'd like there to be a manually entered peak white field in the White Balance module for those that just want a quick look at things, along with a numerical gamma value. If I recall correctly, the Gamma module values aren't retained when you save the calibration, so if you want to do a spot-check you'd have to go through that process all over again.

Now it's been awhile since I used the Gamma module, so I may be very wrong with my points.
post #3684 of 5355
I see. Thanks. I guess in my situation I could not do as you....the Y value changes as the lamp ages and it's important to have the correct (current) Y value in order to properly set gamma. But, I also like to take all the (5%) readings to see a trend, etc.

This brings up another request....It would be nice if there was one master checkbox (that would select all 5% values at once) rather than a checkbox for each 5% value.
post #3685 of 5355
I have been running version 2.2.13 since it was released. Yesterday I upgraded to the current version 2.3.2. Also I have been running version 030112 on my Lumagen Mini 3D. Yesterday I upgraded it to the current version 103012. After 140 hours lamp time on my JVC RS45 I decided to check its calibration using Chromapure's automated calibration routine. The results were horrible! Both chroma and gamma/gray scale were bad. I am talking unwatchable bad. So bad that the only thing I could do was to default gamut and gamma settings in the Mini. Has anyone else had problems after upgrading a Mini or Chromapure skipping so many interim versions?

Happy holidays,
Dennis
post #3686 of 5355
Denis. The one thing you need to make sure you do before pressing the 'start autocal' button is to make sure you have set the basics first:

Contrast, brightness and 100% whitebalance using the display's controls. You must do this with the Lumagen CMS/greyscale set to default. If it has your last calibration setting in the Lumagen then it might slew the 100% adjustment. The autocal will then clear the CMS/greyscale before it starts, so you could set off with an offset for example and then the autocal calibration will end up with a poor result. Easiest check for this is to look at your 100% greyscale measurement on the pre calibration section. If it's more than 3dE out then maybe this is what you did wrong?
post #3687 of 5355
Quote:
Originally Posted by PE06MCG View Post

Hopefully Tom will not see this as impertinence and perhaps there are extremely good technical reasons why this cannot easily be done, but that's my explanation of my previous post.
I don't I see anything as impertinent.

I have 2 concerns about putting a gamma reading in the White Balance module.
1. It is redundant. It would provide nothing that isn't already in the Gamma module. I understood why folks wanted RGB data in the Gamma module. I find the need for gamma data in the White Balance module harder to understand.
2. It adds a layer of complexity to the White Balance module that wouldn't otherwise be there. It is not just an extra data point. It also adds the requirement of first taking a reading at 100%, because gamma cannot be calculated until you do this.

I don't think that the example of color space drop-downs in the Color Management module offers a useful analogy. Selecting a working color space and a target Gamut are requirements for color management. Selecting a particular gamma response is not a requirement for getting good white balance. I get that some want to do both on the same screen, and I agree. This is what the Gamma module is for.
post #3688 of 5355
Quote:
Originally Posted by Greg1981 View Post

My issue with the Gamma module (and this only pertains to what I talked about; the module itself is just fine) is that I would have to go through a complete greyscale run before I can select individual greyscale values (including having to check boxes at 5% intervals). It makes it a little more time-consuming to do a spot-check on specific values. In addition - and this may only apply to a few displays like my own - my 100% White Y value inflates a bit (ex. 103.5 cd/m2) before it stabilizes at a certain value (100 cd/m2) for ~90 seconds, and then the ABL kicks in and the luminance begins to drop. That's why I'd like there to be a manually entered peak white field in the White Balance module for those that just want a quick look at things, along with a numerical gamma value. If I recall correctly, the Gamma module values aren't retained when you save the calibration, so if you want to do a spot-check you'd have to go through that process all over again.
Now it's been awhile since I used the Gamma module, so I may be very wrong with my points.
I think that this is better addressed by just making some small changes to the Gamma module. It would be easy enough to make all of the levels accessible without having to take a full grayscale run. Regarding the ABL issue, just measure 100% once when it is at the optimum level. Don't remeasure unless you actually make calibration changes that require a re measurement..
post #3689 of 5355
Quote:
Originally Posted by tibia View Post

I have been running version 2.2.13 since it was released. Yesterday I upgraded to the current version 2.3.2. Also I have been running version 030112 on my Lumagen Mini 3D. Yesterday I upgraded it to the current version 103012. After 140 hours lamp time on my JVC RS45 I decided to check its calibration using Chromapure's automated calibration routine. The results were horrible! Both chroma and gamma/gray scale were bad. I am talking unwatchable bad. So bad that the only thing I could do was to default gamut and gamma settings in the Mini. Has anyone else had problems after upgrading a Mini or Chromapure skipping so many interim versions?
Thank you for posting your horrible experience on an open forum rather than first contacting technical support.

1. Use 10% gamma increments.
2. Setup the Lumagen to display 75% intensity test patterns.
3. Run both grayscale/gamma and color gamut (not one just one or the other).

Try again.

There is a bug in 2.3.2 with standard Lumagen auto-cal (advanced auto-cal is fine) that crops up occasionally that we have not figured out. If this doesn't fix the problem, I can give you a beta build that definitely does.
post #3690 of 5355
Quote:
Originally Posted by TomHuffman View Post

I have 2 concerns about putting a gamma reading in the White Balance module.
1. It is redundant. It would provide nothing that isn't already in the Gamma module. I understood why folks wanted RGB data in the Gamma module. I find the need for gamma data in the White Balance module harder to understand.
2. It adds a layer of complexity to the White Balance module that wouldn't otherwise be there. It is not just an extra data point. It also adds the requirement of first taking a reading at 100%, because gamma cannot be calculated until you do this.

I agree with Tom. Although I have a Samsung with only RGB white balance control without gamma, combining RGB and gamma complicates things. It is easy enough to change parameters to achieve one target (white balance or gamma). Changing 3 RGB parameters to achieve two targets at the same time makes things complicated.
Having Gamma in the white balance module also (over)complicates things.
If you are experienced, you can handle these things. But one aspect that attracts me to Chromapure is the ease of use with a linear approach. Even though I can handle complexity now, I would prefer to keep the ease of use linearity, making alternatively greyscale and gamma, but not both together. This makes it easier to keep an overview.
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