Okay, Bill.
Rich, as always thank you for your interest.
1) The paper is not bright enough. Have you compared the paper white to GRACoL's white point?
My white point is 92, 1, -2, which I believe is within the tolerances of L ≤ 3 and a and ≤ 2 to 95, 0.0, -2. By the way we use the same semi gloss stock with the same white point on our flexo presses with a pretty good success of matching ISO 12647-2.
2) Your conclusions about device links are not quite correct. The gamut mapping is dependent upon the rendering intent chosen when you build the device link. Going from a smaller to a larger color space with a colorimetric rendering intent, should produce no real movement in colors. There would be a change in the colorants used to hit that color, but the result should have the same appearance. Now, if you used a saturation rendering intent, then the colors would be pushed out to greater saturation.
3) I'm trying to get my head around your color conversions. You indicate that you're converting RGB to 7-color, but with GRACoL as the source. I'm not following you here.
As far as I can tell, the Esko software strips any profile on the incoming file then converts it to the source profile, then to the destination profile. While I can submit a file with and RGB image, the strategy destination profile has to be a CMYK profile. The reason I was selecting GRACol as a source was my attempt to force the software to convert the CMYK to GRACol numbers but allow, where deemed, adding OGV to better express the color that are outside the CMYK. The RGB to 7 color conversion was done in Photoshop in the hopes that the conversion would allow colors to be preserved that were, once again, outside of the CMYK gamut. Since the default densities are not as close to ISO 12647 as I would like, converting the file with both the source and destination profile in the color strategy would not achieve the results I want. I did though try that and felt the results did not convert the image to better match the look of the RGB image.
4) If you're going from RGB to 7-color, what is the purpose of using a device link profile? And how are you constructing the device link? Are you taking an RGB image into GRACoL and then into the 7-color colorspace? Why not just go from RGB straight to the 7-color colorspace?
