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Hi,
See below for a description of the color profile issue I'm having. This may be an obvious question but I searched extensively and couldn't find an answer. I am definitely still a noob when it comes to color management. Thanks in advance for any help!
Best,
Nate
So the answer was pretty obvious...but like I said I'm a noob. I hadn't realized it was possible to just extract an icc profile from an existing image. A number of software can do it, I used Imagemagick (see thread below for details). When I applied the extracted profile to my IM-created TIFF, I was able to perfectly reproduce the color.
http://www.imagemagick.org/discourse-server/viewtopic.php?t=17737
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See this thread. XYZ Colorspace conversion Photoshop CS2 You might want CIE XYZ not Adobe.
I really don't know anything about or use this color space technology, but I can at least try to get you somewhere.
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Thanks gener but I think the link I provided is the link to the CIE XYZ profiles (see link below). Someone please correct me if I'm wrong though.
Like I said, of the icc's downloadable on that site the D50 version gives the closest match to PS but it's not perfect. The reason I think the profile I'm after is an Adobe proprietary one is because I found an Adobe copyright embedded in the the PS-created image's color profile information.
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XYZ is one of the two native spaces of ICC profiles. So an XYZ profile is hardly a profile at all, it's just a "do nothing" profile with some headers. I mention this because, if I was programming an app that needed to embed an XYZ profile, I'd just make one in memory: no need for an external file to exist.
No idea why Adobe would use XYZ for 32-bit images unless you converted it that way. XYZ is _not_ a kind of RGB, and so this is not going to contain RGB values, but some conversion of them. You'd have to match the conversion, not the RGB values.
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Ok, from some study I think I understand that a 32-bit ("HDR") image doesn't have an RGB colour space, so there are none of the problems associated with saving with a different space. It uses a fixed space which can show every possible colour, including those outside any RGB gamut (and many imaginary colours, which I don't really understand). So, while you enter RGB values into Photoshop for a 32-bit image, they are immediately converted from the working space to XYZ; the numbers you type are never stored.
So, unless ImageMagick does the same thing, you need to specify XYZ values, not RGB.
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Thanks this definitely gives me more to noodle on. Just to give some more background, I've created two TIFF files that illustrate what I'm seeing (one PS-created and one IM-created). They are both 1x1 pixel 32-bit TIFFs but if you open them in Photoshop (and zoom in) you will see the color representation is slightly different.
Solid_Green_PS.tif (PS-Created)
Solid_Green_IM.tif (IM-Created)
The only difference I can find between these two TIFF's are their color profiles. When I look at the embedded icc information for each image the PS-created one has the following:
icc:copyright: Copyright 2017 Adobe Systems Incorporated
icc:description: XYZ Profile
icc:manufacturer: XYZ Profile
icc:model: XYZ Profile
Versus the IM-created file, which shows the D50 XYZ Profile I assigned:
icc:copyright: Copyright Hewlett Packard, 2006
icc:description: D50 XYZ profile
icc:manufacturer: D50 XYZ profile
icc:model: D50 XYZ profile
So I guess my question is still the same as the OP, where do I find the Adobe XYZ .icc file that is assigned to the PS-created image so I can assign it to my IM-created image and make them perfectly match?
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So the answer was pretty obvious...but like I said I'm a noob. I hadn't realized it was possible to just extract an icc profile from an existing image. A number of software can do it, I used Imagemagick (see thread below for details). When I applied the extracted profile to my IM-created TIFF, I was able to perfectly reproduce the color.
http://www.imagemagick.org/discourse-server/viewtopic.php?t=17737