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+--- Thread: Question about color spaces in GIMP (/Thread-Question-about-color-spaces-in-GIMP)
Question about color spaces in GIMP - TheGrayMan - 11-21-2023
Hey,
there's a nice website: https://www.wide-gamut.com/test that helps you check whether display supports wider gamut by showing you a simple image saved with P3 .icc color profile. You should see a "W" on the lighter red background if you have HDR turned on and uniform red on SDR displays.
I saved the image on my PC (also attached in post) and opened it with GIMP. When GIMP asks to convert the image to GIMP built-in SRGB I refuse and just keep the P3 .icc profile. Then what's weird for me is that it seems the image is composed of 2 colors outside of 0-255 range. Another weird thing is that at the top of the GIMP's window it's said that the image is 8-bit. These 2 things already seem self-exclusive... Screenshot attached.
Does anybody know what's going on with those values? Correct me if I'm wrong but I think assigning an .icc profile to the image does not change its values at all and the actual color values are still internally saved in 0-1 range. Icc profile is just a metdata that display can interpret to know that color values in this image should be mixed corresponding to color primaries from P3 color gamut and not SDR, right? So these weird values... - could it be GIMP's way of showing colors in wider P3 gamut but still as if corresponding to the color primaries from SDR gamut?
Will be grateful for any hints ; )
RE: Question about color spaces in GIMP - rich2005 - 11-22-2023
no replies as yet ?
This no explanation, just an observation.
In my Gimp setup I have color-management (in Edit -> Preferences) Turned off. If / when I want color management I do it from the View Menu. Nothing special for a display, a reasonable HD laptop screen.
[attachment=10642]
(1) Opening the image-red-p3.jpeg, remember no color management, I can see the W as per the browser test. Using a couple of sample points they do show as out of gamut, greater than 100%
(2) Enable color management and the W vanishes. According to the sample points still out-of-gamut and if you enable soft-proofing/mark out-of-gamut then the whole image is marked.
(3) Image -> Color Management -> Convert to color profile -> Gimp sRGB and the color is clipped to 100% / 255
You could also look into Krita which has more tools for converting color space. This a visual display of the icc profiles.
[attachment=10643]
RE: Question about color spaces in GIMP - TheGrayMan - 11-27-2023
Thanks! That sheds some more light into what's happening, didn't know about this color management setting