Re: Curves for digital Negatives with Epsons

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From: Editor - P.O.V. Image Service (editor@p-o-v-image.com)
Date: 05/26/00-10:33:10 AM Z


DFStein@aol.com wrote:

> As a beginner I am getting confused. Just what are these curves. Are we
> talking about the ColorSync profile or ICC profile or something else.
> Sincerely,
> David Stein

Curves...

Traditionally, these meant a log diagram of exposure vs density (measured by
densitometer) for a paper or film...

In Photoshop one can adjust a set of curves (B&, RGB, or CMYK as
appropriate) that will alter the color values at specific points along a
curve that represents varying tonal values (from dark to light - by
default)..

Profiles:

Are the ICC or ColorSync files that one uses to ensure the there is
consistency in output/input/display from varying devices.. A monitor, a
printer, a scanner, as examples..

These profiles do not actually affect the curves of an output file. The just
translate the output so that the results are consistent across devices.. A
rosetta stone for output/input devices if you will..

That said, suppose you have no profile for a particular printer...

You can play around with the actual curves back in photoshop until you get
one that gives you an accurate compensation for the device.. It's not
elegant, but it works.. You need to save the curve and load it AFTER all your
other work in PShop is done, and then print the file..

I would NOT save the file again after applying the curves in a case like
this..

That said, there is commercial software available that will let you actually
create relatively accurate (depending on how accurate you need them) profiles
for devices you have no profile for..

Keith

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