I’ve got a question for people familiar with the
neutrals analysis function in ColorShop X.
I’m making a series of CMYK profiles at various
settings in order to try to maximize dMax, device gamut and neutrals
accuracy. (Yes, I know…..) J
So, I have tried several per-channel ink limit
settings/linearizations in the RIP. For a given RIP set-up, I have tried
several different total ink limits in the profiling software. In both
Gretag and Monaco I have used a black GCR curve that is a straight-line,
45-degree “curve (called MaxK in Gretag). Max black is set to
100%. For each ink limiting set-up in the RIP, I make a series of
profiles in both Monaco Profiler 4.8 and Gretag ProfileMaker Pro 5.0.5b at
total ink limit increments of 10, from about 320 down to 200. Then I open
the ColorShop X Profile Viewer, add in all the profiles from the set, (Relative
Colorimetric rendering) and then look at the Neutral graph/data and compare the
various profiles in the set, looking for the best one.
What I’m looking for in ColorShop X is the profile
that produces the lowest output L* for an input L* of 0, while at the same time
produces the lowest Max Chroma error. Here are my observations for any
given RIP setup followed by some questions:
Monaco consistently has lower max chroma error. The
value varies, depending on the ink limits in the RIP and the profile, but the
values are typically half that of the Gretag profiles (e.g. for one particular
matte paper, at the highest dMax, I get a max chroma error of about 1.25 in
Monaco vs. 2.50 in Gretag). Since I’m viewing the Relative
Colorimetric neutrals, I would expect that gamut mapping choices (Like LOGO Colorful)
shouldn’t matter. I wonder why Gretag doesn’t do a better job
at neutrals?
Gretag consistently produces a lower dMax (higher output L*
-- i.e. ligher) than Monaco. The difference is typically 1 to 1.5 higher
in L*. For a given ink limit in the profile, the difference may be even
higher. Typically, the highest dMax from Monaco occurs at a different
total profile ink limit than in Gretag.
Monaco consistently hits dMax prior to input L* of 0 then
reverses and gets slightly lighter for the lower input values. For
example, for a particular paper with a dMax of L*=17, Monaco will hit this at
about input L*=17. Then, for input L*=16 down to 0, it will reverse a
little and produce slightly lighter output values (L*=17+). This happens on a
variety of papers with a variety of RIP set-ups so it must be a problem with
Monaco profiler. Yes?
When reviewing the device colors in the Neutrals Graph data
tab, I see that Monaco builds up black ink to 100, where it hits the dMax for
the paper, (in the case above, around input L* of 17), then reduces(!) black to
98, 97, etc. from L*=16 to 0. Gretag doesn’t seem to reverse the
black build-up but at lower ink limits (280 and below) it will not even hit
100% black ink. Why is this happening? Why does Monaco hit 100 and
decrease and why does Gretag not reach 100%? For this particular paper
and ink, it seems the more black ink I can get, the darker the dMax, so I
don’t understand why neither is obeying the 100% setting! Any
ideas?
Thanks,
Michael