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Re: [QuadtoneRIP] Re: Measuring Relative Ink Density

2005-11-27 by Tom Husband

Thanks again Roy. That makes sense. It'll be interesting to see what things look like when I redo the curves.
Tom
----- Original Message -----
Sent: Saturday, November 26, 2005 11:41 AM
Subject: [QuadtoneRIP] Re: Measuring Relative Ink Density

Hi Tom,

What I do is measure each gray against the next darker gray. There are two
reasons for this:
1) that's the transition that will happen on the print
2) measurements are more accurate. a 5% gray is a lot easier to measure
against a 10% gray rather than the 100% black.

However the numbers entered are always relative to black. So you multiply
the new factor by the factor of the darker gray. For example: measure a
dark gray to black and get 30%. Then measure a light gray against the dark gray
and get 40%. ; So the final values are K=100, DarkGray=30 and LightGray=12
since 40% * 30% = 12%

In practice its probably not a big deal for just 2 grays. When you get to 7 grays
I think it would be really hard to measure. The linearization later on tends to
fix up the transition too.

Roy







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