I've experienced the same problem too. Rel Col gives me K 98.9% while
Perceptual gives K 100% for a total ink limit of 350%. It's an oddity with
the way ArgyllCMS computes the combination of CMYK. It is quite buggy. To
be honest, I don't think it is 100% reliable for making CMYK profiles, but
I need it for the (nearly perfect) luminance-preserving gamut mapping that
Graeme has included on my request.
There is another problem, you might have noticed that the profile (nearly)
reaches the total ink limit at about L*10-15, then drops the total ink
before reaching the total ink limit once more at dMax. When you graph the
neutral rendering curves in ColorThink Pro it looks very odd indeed.
I've tried to raise the issue with Graeme but he does not know why this is
happening. You can read more about it here:
There are other issues about shaping the black ink curve earlier in the
same thread, if you are interested.
On Thu, 21 Mar 2019 at 14:25, Stephen Marsh <stephenamarsh@xxxxxxxxx> wrote:
I have searched the archives however I could not find anything on this
topic. I have a total ink limited CMYK press profile created by ArgyllCMS
that delivers a nominal ~240% total ink limit.
Relative Colorimetric intent delivers 47c 41m 39y 98k
Perceptual intent delivers 50c 43m 42m 100k
Despite setting the K limit to 100, the relcol conversion maxes out at
98%, is there any way to get this to 100% black by editing the .ti1 or .ti3
On a similar note, is it possible to create a custom “build” for the total
ink value, such as an “idealised” 60c 40m 40y 100k build (that may not be
neutral, but satisfies the humans in the workflow)?