T42 calibration using Adobe Gamma

[kc]

I'm using Photoshop CS with a 2378-FVU (Radeon 9600) and am having trouble calibrating the LCD with the Adobe Gamma application. As indicated in a prior post, AG controls do not function with the T42 as configured (the adjustment sliders move, but nothing changes). As a workaround, I launched the ATI control panel and made the suggested brightness, contrast and channel gamma adjustments using the ATI tools and the AG output for calibration. I am not confident that I I have successfully calibrated the LCD.

Any advice or suggestions are welcomed.

Thanks.

[dvorak]

I'm having a hard time understanding why does one need to calibrate the LCD on a laptop. The displays I've seen (I'm talking about Thinkpad LCDs) have serious vertical color inconsistency, hence some tones of blue appear violet on one end and light blue on the other, this makes me confused to what the original color is and that's not something that goes well with graphics work.
I really suggest you use an external display if you wish to do any real graphics work that requires true calibration.

Good luck anyways!

[Cavorite]

Eh, I have done color calibration on LCD's and had it turn out well, but I've used an actualy calibration device to do so, and it's best to do it fairly frequently.

-C-

[kc]

After reviewing postings at the Adobe forums, it appears that Adobe Gamma does not operate with most LCD/graphic card combinations -- and more importantaly-- is not designed for LCD adjustment.

However, the question still remains -- how do I choose the best combination of brightness, contrast and gamma using the ATI driver color controls.

I concede that my T42 is inferior to a well calibrated CRT for serious phototshop work, but I assume that their is a "preferred" adjustment for my laptop.

[Sasha]

You can check out this website

http://www.normankoren.com/makingfineprints1A.html

Step 1:

Since you cannot set the contrast on your LCD, use WiziWYG (download available on the website), set your brightness and contrast and create an ICC profile. Write down the brightness and contrast values from the ATI Control Panel.

Step 2:

Use QuickGamma (download available on the website) and use the help file to set the Gamma values for your LCD. Again, write down these values.

This has helped me in achieving reasonably accurate color representations (considering a LCD monitor).

HTH

[kc]

Thanks for the suggestions -- I'm already giving it a try.

Some specific questions about your technique:

1. With WIziWYG, I'm on the brightness/contrast test. When I follow the instructions literally (brightness and contrast full up -- reduce brightness to expose gray box in black, then reduce contrast to expose dark box in white area), the black box drops below threshhold when I reduce the contrast to the appropriate white box level. Is it correct to adjust these independently, or am I adjusting to achieve threshhold levels on both the white and black settings?

2. Do you stop at this point, or use the next set of RGB screens (looks like gamma adjustment test on Adobe Gamma)? If so, what do you adjust?

3. How do you add the results from the Quick Gamma to create your ICC profile?

Sorry about the elemental nature of these questions, but I want to benefit from your good experience.

THanks for the help.

[Sasha]

1. They are independent. So when you are adjusting the contrast and the white boxes disappear, dont' worry. You have to use each set of boxes seperately for setting the brightness/contrasr

2. You can stop at this point. However, I suggest that you go ahead all the way to the end and create an ICC profile. If some software palys truant with your monitor settings, you can use the profile to restore settings. The adjustments after the brightness/contrast part is basically setting the White Point, which is of not much use on an LCD. Also, you will be using Quick Gamma later on for setting the Gamma.

If you want to reduce the brightness of the LCD more than the IBM settings allow, you can download a program called the Brightness Controller from the NEC-Mitsubishi site. This allows you to reduce the LCD brightness to much lower settings than the Thinkpad default settings. I found that my LCD was too bright for photoediting even at the minimal settings. For my screen, my settings for brightness and contrast are 4 and 122.

3. QuickGamma is used for setting Gamma values. Gamma is a function of the contrast of the monitor. But, we cannot adjust the contrast of a LCD monitor. Contrast for LCD monitors is adjusted using the backlight (indirectly the brightness). To the best of my knowledge, gamma values can be used independently across ICC profiles. QuickGamma has an option that loads it at boot up and activates the gamma settings when an ICC profile-aware application (ala Adobe CS) is active. My settings for Gamma are 1.82, 1.82 and 1.58 (for R, G and B)

I have learnt so much from this forum that it is a pleasure to give something back (atleast once in a while.... )