Re: G7 and SWOP 11 ICC profiles available at TGLC inc.
Re: G7 and SWOP 11 ICC profiles available at TGLC inc.
- Subject: Re: G7 and SWOP 11 ICC profiles available at TGLC inc.
- From: Jim Rich <email@hidden>
- Date: Thu, 07 Dec 2006 12:11:41 -0500
- Thread-topic: G7 and SWOP 11 ICC profiles available at TGLC inc.
Roberto,
It is my understanding that the value of 95% black is just a target that is
near to the end of the curve. And is it based on the amount of CMY in the
shadow.
So instead of using 100% black, the end-user has some head room while being
close to the end of the black curve. Since it is a black point target
value it can change based on the printing process.
An example of how the black value changes is when a full range color
separation is created using say 95% cyan, 85% magenta and yellow and using
80% black. That would be a total area coverage (TAC) of 345%. But when
applying a TAC of 300 with UCR you would get say 75% cyan, 65% magenta
and yellow and using 95% black.
It is not so much that an end-user needs to nail the black at 95% or more,
what is important is to find the combination of halftone dot values that
create the blackest area on a printed sheet of proof. In some cases,
higher black dot values don't mean blacker shadows, due to phenomenon like
additivity failure. One method to determine the optimum CMY and K combo is
to use a spectrophotometer to sample CMY and K combinations and then find
the lowest L* values of those different mixtures of the CMYK shadow values.
Jim Rich
On 12/7/06 11:17 AM, "Roberto Michelena" <email@hidden> wrote:
> I've always wondered where this long established use of 95% maximum
> black (or even 90% in some cases) comes from... what's the reasoning
> behind it?
>
> -- Roberto Michelena
> Infinitek
> Lima, Peru
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