re: Black Generation Question
re: Black Generation Question
- Subject: re: Black Generation Question
- From: Chris Murphy <email@hidden>
- Date: Sat, 3 Feb 2001 12:38:54 -0700
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In the case of the job I've been working on creating a profile for a
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Kodak DCP 9500 proofer to simulate the client's Dupont Waterproof, I
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got good results (better than the Kodak guy according to the client),
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although the Dupont gives deeper blacks.
That's because it's an analog laminate proof. It will give you deeper
blacks. And it will produce a denser black than even the press can. The
pressmen will know this through experience that they just don't get those
levels of black. And second, the CDP 9500 might not produce as black of a
black as a press can (depends on the inkset being used). So when it comes
to density, you're probably just going to have to give up.
What you can experiment with here is total ink limit. You will want to
build a profile that they use for separations with the proper ink limit
of course; but for proofing you might need to fudge on the ink limit
(i.e. make it higher) in order to get more density on the 9500. You
might even consider reducing it on the analog proof - but if they are
making films to make that proof, they will likely use those to make
plates. So more than likely you'll have to use the same profile for
making separations as for making the Waterproofs (and hence separations
for making plates) - which means it needs to be set at the right ink
limits.
Also be aware that on press, you usually don't want 100% black in images.
An analog proof will let you print with 100% black and won't show you
what the consequences are. So you might need to experiment with a range
of black ink limits. Make sure you check their black ink density on press
as you are doing this so you can learn the relationship between K SID and
black ink limit. (Dot gain also will affect what black ink limit you will
need as well.)
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I guess the bottom line question is, how does black generation
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visually affect the print? I would think that increasing it would
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give deeper, more solid looking blacks, but not having time to
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experiment, I'm only speculating.
Not really. Increasing black generation increases the replacement of CMY
with K. Sometimes you can replace too much with K only and then you need
some UCA at the top end to add in more CMY to get a richer black. That
might be part of the problem with the 9500.
A TAC test chart (total area coverage = ink limit) can be very helpful in
determining ink limits and black generation.
Also note that black generation is IMAGE specific. Not just device
specific. So you will need to find the right compromise black generation
for the proofer because obviously one black generation is going to have
to do for everything. (Depending on their workflow and kind of jobs they
print, it might be possible to have profiles with multiple black
generation for proofing - but I would consider this only if one black
generation isn't working out.)
Chris Murphy