Re: CMYK output profiles & dotgain
Re: CMYK output profiles & dotgain
- Subject: Re: CMYK output profiles & dotgain
- From: Marc Levine <email@hidden>
- Date: Wed, 04 Feb 2004 22:54:21 -0500
>
Can you FIND what the actual dot gain is in the profile? THAT'S not so
>
easy unless you know what sort of tone reproduction characteristics the
>
profile has.
Bebris,
I would try not to think of the profiling process in terms of compensation.
Compensation typically refers to the process of creating a 1D curve to alter
the printing behavior of a device.
What profiling does is capture the printing condition of a device and allow
you to do 2 things:
1) Convert colors into that device space accurately so that the press output
is measurably accurate (in Lab) to your original expectation. Remember that
applications like Photoshop are all Lab under the hood. What this means is
that, when you look at a file on your computer, you are seeing Lab values.
Of course most of the time, your file data is probably in RGB or CMYK.
However, Photoshop simply cross references the data using either the default
workspace profile or the assigned profile and gets a Lab value. That's what
you see on the monitor. Your press profile will let you turn that Lab data
into CMYKs for your press that produce the correct color.
2) Simulate your press color on another device. Once you have an
understanding of the relationship of your press recipes to real color (aka
an ICC profile), you can install the profile in a RIP as an input profile.
This way, when you feed the RIP the press separations, it can figure out
what the correct lab info is for that particular job and then send those
Labs through a proofer ICC profile and achieve your press color on your
proofer.
Back to the point. All of the things such as density, dot gain, trap, gray
balance, etc are defined prior to making the ICC profile. These attributes
dictate that press condition which is then described by the ICC profile. You
could say that the resulting profile inherits these attributes. However, I
think it would be more accurate to say that density, etc... are for making
sure that your press is mechanically configured to print CMYK in accordance
with some target numbers. Profiles are more about describing the
relationship between your CMYK recipes and real output color.
The concept is that, in keeping your press running to consistent numbers,
you can use the profile to both produce separations that take advantage of
the press capabilities, and enable your displays and proofing systems to get
a very accurate simulation of the press prior to starting your make ready.
Dot gain, trap, density, etc.. Are the measuring sticks by which you
"calibrate" and control your process color on press. The ICC profile simply
lets you get color from one device to another - monitor to proofer to press
to toaster to blender.
Hope this helps.
Marc
--
Marc Levine
Sales Guy
Technical Guy
Monaco Systems / X-Rite, Inc.
www.monacosys.com / www.xrite.com
email@hidden
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