A while back I created a color target for assessing display calibration accuracy especially for gamma and color matrix formula transform in color managed apps.
These colors were derived from years of noticing their hue/saturation response shift in Photoshop on a Mac system when loading different display profiles that used inaccurate color matrices encoded within their build.
Some of these matrices=(mathematical descriptors of combined display colorant purity's and color temp) are embedded within the default profile built by the system whenever a new display is connected and not profiled. Most displays somewhere in the late '90's had their color responses measured and written into their ROM chip by the factory in standard EDID format. Often they either were inaccurate or were written in such a way that induced the OS to create a corrupt default profile causing hue/saturation shifts in Photoshop.
Mac's eyeball calibrator in OS X automatically derives these EDID numbers whenever you see "Color LCD" or the manufacturer's brand name in a profile the user didn't install.
Anyway, here's what to visually test for in this target, it's in the AdobeRGB space so it needs to be viewed in a color managed app:
The small squares in the center of the bigger squares should not be more noticeable in luminance than the differences seen between the solid black square and the gray square right above it except of course for the Golden Yellow square and blue gradient-(my homage to Maxfield Parrish).
The red in the Xrite color chart should not look orange or magenta. The baby on the far right should have a more noticeable amount of yellow in its peachy pink tan complexion compared to the pink baby second from the left. And none of the colors in the entire chart should be glowing (blooming) or appear over saturated.
Hope it helps, cheers!
Tim Lookingbill
[attachment=19478:ColorSqu...inTarget.jpg]
Thanks Tim,
I also did something similar myself. Since I do own a ColorChecker Passport, I went the dumb way. If the purpose of that target and software is to generate a proper camera profile, then, by properly lighting it and metering it, that image, once white balanced and profiled, should give an image of the target comparable to the target itself.
The several online target-images available looked "washed out" for me, and I was thinking either my screen or my Spyder had a problem. But both your photo and my own image of the target ( with the DNG profile created by the CC Passport plugin ) were spot on. My own image a bit more than yours, but both were more accurate to the actual physical target ( placed side by side with the screen ) than the downloaded patches. But even the downloaded patches didn't have color changes, as I could see the same colors, without even slight variations, it just looked "washed out".
I also did the test suggested on "Real World Color Management", page 220 ( Chapter 9 - Figure 9-1 ), which is their Black Point Check. They state an excellent calibration system should see a difference between level 0 and 1, and a typical system, around 5 or 7. I noticed a change right on the first level, without color casting.
I guess that leaves me with some peace of mind. Yes, it's a notebook screen, it will never be perfect, but at least my Spyder doesn't seem to be giving me false colors, or making images so bright, I could get an exposure wrong, which were my biggest fears. I still want to go towards a i1Pro and good external monitor when my budget allows. But I don't think I need to replace my colorimeter right now. Maybe I got lucky and got one of the "good" Spyder3 units.
Anyway, it was also a couple of days of testing every possible white luminance, black luminance and recalibrating and comparing the CC Passport to images of the target, trying to find significant shifts, aberrations, and in the end all the hard work turned out fine
Thanks everyone, I really mean it, all the help in this forum was really important, even to wonder what else I could check and do and test and see how to improve.
And here's what I did to manage a decent calibration on my MacBook Pro 13" screen.
Software: ColorEyes Display Pro
Hardware: Spyder3
Monitor Settings: Apple Cinema Display,iMac, Laptop
Profile Settings: ICC v4
White Point Target: D65, 110cd/m2
Gamma: 2.2
Black Point Target: 0.35cd/m2
I guess it helps. By the way, the native white luminance of my display is around 195cd/m2. And I did add a few custom gray balance points ( 138, 114, 86, 74, 54, 36 ), because I could see some banding forming on the scale.
