Graeme Gill wrote:
The total ink limit is a maximum, not a target.
I'm with you. The behavior of a CMYK device near black is not usually simple. In
general there are multiple overlapping, discontinuous regions. For a given target color (say L*a*b* = 0,0,0) it does not follow automatically that the closest color will use the maximum possible ink. Some inksets have non-monotonic behavior near black (ie., often adding yellow makes things lighter for some pigmented inks).
Any suggestions on how to find the true TAC? Having said that, I don't get quite the same results as you:
icclu -fb -ir FOGRA39L.icm 0 0 0 -> 1.000000 0.856338 0.575142 1.000000 with the sum 3.43148, but that's with my development code, which may be a little different to the current release.
I can't get those numbers at all. Going from L*a*b* = 0,0,0 to CMYK (rel.col.) I get: 0.874157 0.770432 0.600203 1.000000 (ArgyllCMS) 87 77 60 100 (Photoshop CS2, Adobe (ACE)) 87.4189 77.0321 60.0153 99.9969 (LittleCMS, icctrans.dll for Matlab) (you didn't do a new profile with the FOGRA39L-data with your development code then running icclu?) Martin Weberg