Legacy ImageMagick Discussions Archive

I notice that the TIFFs I process with IM, which have the AdobeRGB ICC profile embedded, are displayed by the "display" command as if they were sRGB or had no profile. (In my experience, files with no profile or using sRGB look identical on a computer monitor, understandably.) But when I bring the image into GIMP, which is colour managed, the view is noticeably different, usually more saturated and slightly more contrasty.

This tells me that IM is not colour managed. The display command ignores the AdobeRGB profile and display the image "as is", which is closest to sRGB.

I understand all the things one can do with the "-profile" command, but I have seen nothing in the documentation as to what effect an embedded profile might actually have on the way the image is processed.

My impression from reading about the gamut difference between sRGB and AdobeRGB is that processing an image in AdobeRGB is preferrable. Is there actually any truth to this? Or are all calculations really profile-ignorant, even in a colour managed application, and the profile merely affects how the image is displayed?

At the present time I only use IM in automation, with "display" being used only for checking focus. But I would like to do interactive processing with IM, where the look of the result becomes very important. There's no point interactively processing colour balance with IM, if the display is wrong. So my final question: are there any plans for making IM colour managed?

I am not the expert on this. But I don't think IM processes images in the profile space, but just passes the profile on in most cases to the output image.

With regard to the display, if you are in Unix, then IM uses X11 and I guess it depends upon how X11 does its display. But see http://www.imagemagick.org/script/display.php about using -profile option in your display command.

For example

display test4_cmyk_whiteback.psd

The above displays looking negated, but the following looks correct.

display -profile Profiles/CMYK.icc -profile Profiles/sRGB.icc test4_cmyk_whiteback.psd


But if I do

convert test4_cmyk_whiteback.psd -profile Profiles/CMYK.icc -profile Profiles/sRGB.icc test4_cmyk_whiteback_profiles.psd

to add the profiles to the image, then

display test4_cmyk_whiteback_profiles.psd

looks fine.

So I would disagree with your statement that the display does not use the profiles.

Oh, I get it, thanks, Fred! Basically you're saying you have to convert to sRGB and then it will display correctly. Ironically, I've now switched to an all-sRGB workflow so this is no longer needed, but it's good to know for future reference.

The profiles have to provide the means for the image to be displayed as RGB, while the image can still be CMYK. But the profile can be in the image file itself and does not have to be supplied externally. At least that is my understanding from my tests.