I created a set of 442 RGB values, mostly evenly distributed but with additional focus on shadow, highlight, and gray. I used BabelColor’s PatchTool to create a 16 bit untagged TIFF image using those values.
In Photoshop CS6, I assigned this untagged TIFF image one of my printer profiles. I expected this to turn the image into 442 different colors, all within my printer profile’s gamut. I wanted to print the patch, measure it with i1Profiler, and see how accurate it was.
I’ve found that if I graph the printer profile and the TIFF image with the printer profile assigned to it, as I expected, all the colors are in gamut.
However, Photoshop CS6 can’t print an image through the same profile that the document is in. (It considers this no color management, which is no longer supported.) Rather than using the Adobe print tool for such a case, I figured I could convert this TIFF to ProPhoto RGB, and the LAB colors should remain approximately the same, so all the colors should remain in gamut – or if they drifted outside, they wouldn’t by much.
Much to my surprise, if I then graph this TIFF image in ColorThink, the colors have severely leaked out of the printer profile space.
I’m not sure if this is a Photoshop or ColorThink issue, but I’m probably missing something. The measurements are giving me deltaE values averaging 4 overall and 8.8 for the worst 10% when printing using relative colorimetric, and 2.75 and 9 using absolute colorimetric. In Photoshop, when I make the ProPhoto RGB conversion, I see a slight change in a few of the colors - which is odd to me because the patch has the same LAB values in Photoshop before and after the conversion, so I would have thought they would display on the screen the same.
I also tried without black point compensation and absolute colorimetric, and still have large differences.
P.S. My workflow always involves printing a document that’s in ProPhoto RGB, hence my desire to convert it to that rather than use Adobe’s standalone print tool.
Untagged RGB values, assigned a printer profile
Untagged RGB values, assigned a printer profile, converted to ProPhoto RGB using Adobe (ACE) Relative Colorimetric with Black Point Compensation
Untagged RGB values, assigned a printer profile, converted to ProPhoto RGB using Adobe (ACE) Absolute Colorimetric