Re: GCR and UCR

Re-reading this in the morning light I see that fatigue last night
muddled my meaning, so a couple clarifications are in order:

Katharine Thayer wrote:
>
> Etienne Garbaux wrote:
> >
> > Katharine wrote:
> >
> > > [needing to replace tricolor neutral density with black density] is
> > > only true for printing inks, due to the impurities they contain; it
> > > has nothing to do with the pure pigments we use in gum printing.
> >
> > > I was simply pointing out what happens when you do that; what happens
> > > doesn't make any sense for gum printing, was my point.
>
> First of all, before I even go on to read the rest of this, a mild
> objection to what seems to me an inexplicable linking of two unrelated
> fragments from two completely different posts. The first fragment was
> about the issue of whether you can get black by mixing three colors in
> gum printing. The second was about how Photoshop shifts density from the
> color printers to the black printer when creating CMYK separations. The
> two have nothing to do with each other, and I can't imagine why they
> were put together here.

Rather than saying that these two fragments have nothing to do with each
other, I should have simply said that they are two different issues. I
do of course consider them indirectly related, in that the more print
density is shifted from the color printers to the black printers, it
seems to me, the less likely one would be to to be able to print black
with the three colors, although if I got it right in a quick scan it
looks like Judy took issue with that claim and said that she found she
could get full density and good color balance with the three colors
with the default CMYK separation.

>
> This idea that it is impossible to make black with color seems to be one
> of those deeply held dogmas that don't easily yield to reason, fact or
> evidence, even though it is demonstrably true both in gum printing and
> in painting.

This must have caused some puzzled doubletakes. Of course I meant that
it is eminently POSSIBLE to make black using only color, as any painter
knows and as has been demonstrated for years by tricolor gum printers.
If you don't believe my own experience both in gum printing and in
painting, or my own work that I've already referenced in this thread,
perhaps Stephen Livick can convince you:

http://www.livick.com

If not, we'll just have to respectfully agree to disagree.
Katharine Thayer
Received on Wed Sep 15 08:22:41 2004