RE: TAC and "Total Ink Limit"
RE: TAC and "Total Ink Limit"
- Subject: RE: TAC and "Total Ink Limit"
- From: "CS Carl Stawicki (4211)" <email@hidden>
- Date: Tue, 8 Jul 2003 08:26:03 -0400
Thanks, Terry.
So, the terms TAC and Total Ink Limit refer to what's in the digital file
and plate/film (barring some tweaking). Is there a term that refers to the
total ink coverage that ends up on paper?
Thanks again,
Carl.
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From: Terry Wyse
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Sent: Thursday, July 3, 2003 10:42 AM
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To: ColorSync User List
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Subject: Re: TAC and "Total Ink Limit"
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>
on 7/3/03 9:27 AM, CS Carl Stawicki (4211) wrote:
>
>
> If I convert a 0rgb to US Web Coated (SWOP)v2, I get 75c 68m 67y 90k,
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which
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> equals exactly 300% total ink (Perc., BPC on). Now, I have 2 questions:
>
What
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> are the values of this color that ends up on plate, and what are the
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values
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> that end up on press? (this is a computer-to-plate process)
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>
In theory, you'll get the same values on plate that's in your file. In
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practice, the printer may have compensation curves being applied to the
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plate. That's OK as they are probably applying plate curves to achieve a
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more-or-less standard amount of dot gain on press. The main thing to
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consider is that your press profile targets roughly the same dot gain
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(TVI)
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values that they expect to get on press. It's only when you
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>
>
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> All the values output the same on plate, and gain on press. If this is
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> correct, then I will end up with higher values on press. If you account
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for
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> a 20% dot gain (just to keep it simple), the original 75c 68m 67y 90k in
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my
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> Photoshop file would end up gaining to 89c 84m 84y 96k, equaling 353%,
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which
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> exceeds the TAC of Swop (300%). Is my reasoning correct?
>
>
Incorrect. The TAC is only considered for the actual values in your image.
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While 20-22% dot gain is the EXPECTED amount on press, the TAC value is
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not
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part of this. Another way to look at is the TAC only refers to the
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physical
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values on plate and press and not the final dot area values as measured by
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a
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densitometer. Remember, nearly HALF the "dot gain" on press is purely
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optical gain (about 10-12%) where the physical dot hasn't changed at all.
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The rest of the measured dot gain is physical gain. At any rate, all the
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TAC
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values, etc., already take into account the expected dot gain on press.
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>
Hope this helps,
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Terry
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>
--
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__________________________________
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WyseConsul
>
Color Management Consulting
>
v 704.843.0858
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e email@hidden
>
__________________________________
>
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