Re: Looking for BestColor Expert
Re: Looking for BestColor Expert
- Subject: Re: Looking for BestColor Expert
- From: Terry Wyse <email@hidden>
- Date: Fri, 30 Mar 2001 07:46:51 -0500
on 3/30/01 1:26 AM, Martin Sluka wrote:
>
I did the calibration of BestColor just two days before - baseline
>
linearisation for two papers - total limit set to 200 %. I have use
>
the DTP 41 for measurement. Very easy and fast. The ink limits per
>
channel I have set a bit (+.2 D) than assumed maxD for inks used in
>
print press.
The part about "assumed maxD for inks used in print press" is where I have a
bit of trouble with the baselin procedure. If the RIP is to be used for
proofing, I've heard from several sources that you should set the ink limit
at a density that is close to the solid ink density (SID) of the printing
press being simulated, "close to" meaning set the baselin density possibly
+.10 compared to the press SID to give yourself a bit of headroom when
profiling. So far that makes sense to me. But here's where I think that's a
problem: I'm printing process colors AND I would like to simulate spot
colors on the same proof. To me, setting the ink limits close to the SID of
the press would seriously constrict the available gamut for simulating spot
colors, true?
For "general purpose" proofing where you may be proofing RGB data, CMYK
press simulations and CMYK+spot simulations, here's been my approach:
* Run a baselin procedure and plot an ink density vs. dot% graph. Where you
see the density start to "shoulder off", that's where the ink limit should
be set for that channel. To me, this would be the "best" compromise between
linear behavior without seriously limiting available gamut.
* After setting the per channel limits, run a total ink limit test. I'll
tell you what I use is a custom target I put together that helps me target
the total ink a bit better than the "Quantity of Colors" target. Without
giving away my secret sauce, I use lines of varying pixel widths to
determine how well I'm holding detail. This usually results in a total ink
limit of around 180% on BESTPaper SemiMatte.
Another thing I've found that's more critical than I'd imagined is the
UCR/GCR amount and Black start point settings when making your profile
(total ink set to 400% of course). I've found this has a considerable affect
on smoothness and color banding when printing a gray ramp. This I'll
withhold for now since I put considerable time into finding the "perfect"
setting with my ProfileMaker package. Suffice to say that the "recommended"
Black start point of +60% was not correct for me. I ended up moving the
start point down considerably while being careful not to introduce K in
things such as flesh tones. +/-10% on the start point made a considerable
difference in the final results.
Well, I can see I've rambled on again, time to give the fingers a rest.
Regards,
Terry
_____________________________
Terence L. Wyse
PrePress Systems Specialist
All Systems Integration, Inc.
114 Cummings Park
Woburn, MA 01801
Main office:
781.935.3322 voice
781.935.6622 fax
http://www.allsystems.com
email@hidden
_____________________________