Re: CMYK separations on Adobe Photoshop

Kate M wrote:
>
> I found the comparison of the two sets of negs interesting.

Thanks Kate,
I wish I'd thought to do this years ago, it might have saved me some
grief.

I don't know that there is anything I have said on this list that has
elicited more vehement opposition than the simple statement that CMYK
(meaning here specifically the default CMYK space in Photoshop): (1)
distorts the color information in the RGB file, (2) is about preparing a
file for commercial printing with particular inks and particular papers,
and (3) has nothing to do with gum printing. IMO.

Up til now, I've just demonstrated the distortion by selecting one pixel
in the color image and showing what happens to the color information in
that pixel as you switch to CMYK, by giving the color numbers from the
info palette. (Keith has also shown this, with various CMYK setup
options.) But it wasn't until I printed out these CMYK separations and
had them in front of me that I realized how well the separations
themselves tell the tale. I was writing at the computer, with the
magenta CMYK separation sitting on top of the little pile of separations
on the desk in front of me. and it kept distracting me from what I was
writing. I kept thinking, what IS that? So finally I stopped and picked
the thing up and took a good look at it. I still don't know what it is,
because it makes no sense to me in terms of photography, but I do know
that I wouldn't care to try to print it, or the yellow printer either,
because I don't see how they could possibly give me the results I want.
This is not to say it's impossible, only to say I don't see from the
negative how it possibly could, and I prefer to use a method that makes
sense to me at every step.

The separations from RGB files, I can look at each of the negatives and
know immediately what it means in terms of the original color image and
also what it means in terms of what I'm intending to do with the final
gum print. But these CMYK separations are just... well, like I say, they
make no sense to me at all. But they do show very well the extent to
which the color information in the RGB file is altered in the switch to
the default CMYK.
Katharine
Received on Wed Nov 3 09:07:35 2004