Re: GCR and UCR

From: Judy Seigel ^lt;>
Date: 09/14/04-10:11:27 PM Z
Message-id: <>

On Tue, 14 Sep 2004, Katharine Thayer wrote:

> BUT (and this is important) if you get your three color printers and
> your black through CMYK separations, then of COURSE you have to use the
> black printer, because that's how the separations are designed. Density
> (I'm thinking print density here not negative density) is stripped out
> of the color layers and shifted to the black layer, so of course
> printing just the three colors is going to give you a wimpy unsatisfying
> color print and you're going to need to use the black printer, where
> much of the print density has been deposited. But the point is, if you
> had stayed with the RGB file and kept the straight color information,
> none of this would be necessary.

Well again, this was not my finding. About 5 years ago, or maybe 6, I
decided to try tricolor gum, since before that I'd only done "fake"
tricolor by brushing out areas in 3 (or more) coats printed from one
monochrome negative. (The results, BTW, can be delicious and deliciously

I wasn't a "color" photographer until I began with the digital camera,
which makes color quite effortless and IMO has a great color sense. And on
the few occasions I did photograph in color, got very little to my liking.
But newly in love with gum I decided to do a "real" color photograph in
gum and shot some slide film in front of the house and around the corner.
I scanned the slides on a long defunct scanner and did CMY separations by
the default settings in Photoshop 4 (or maybe it was 3) -- I didn't know
there was any other kind, and having only a 300 dpi laser printer had no
idea of RGB as default, which I gather it is in inkjet. (Whichever scanner
program I was using, also had CMYK as default.)

I'd never heard of a "curve," but printed the separations out on laser
acetate @ 300 dpi, or plain paper that I waxed, again by default -- just
the way the separations broke. I made the gum prints using thalo blue,
quinacridone red (or very early a paint called alizarin crimson), and
Rowney permanent yellow (or similar). Another point of this story is that
the color in the print was in fact too "realistic" for my liking -- the
prints looked so much like "C prints" I thought they lacked edge -- plus I
didn't see the point in going trhough so many steps to get a C print.

I never added a black because there was no place for it to go, and in some
cases the color was actually too intense. Another point (#3?) being that
again, you cannot state an absolute in gum (or rarely). Maybe the dark
color of my gum arabic substituted for black -- though actually as we know
that color sort of burns off in the print. Or my paint somehow went on
thicker, or my paper held more, or whatever... In any event the
"realistic" effects kind of embarrassed me & I didn't do them for long.
Then my scanner went on the fritz, and by the time I got a new scanner I
was working from large monochrome negatives...

But if I've understood this thread, nobody knows what UCR & GCR stand for?
Or maybe I missed that part ? Whichever, Real World Adobe Photoshop 7
says UCR is Undercolor Removal & GCR is Gray Component Replacement & I see
no reason to doubt that.

Finally, speaking of color, I take the liberty of mentioning my daughter's
op-ed piece in today's (Tuesday's) NY Times... "Fade to Black" (if you
have a copy). Oh, it seems to be 12:05 here in New York, so that was


Received on Tue Sep 14 22:11:36 2004

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