RE: Gum Tri-Color Yellow

Traditional colour theory would have it that if you get a brown tone
it's because you don't have a balanced mix of c,m,y. Obviously choosing
pigments that stray away from the printer's primaries will skew the
black tones of overprints towards brown, red, whatever......I have
noticed that brown tone and corrected it with a K separation printing of
Payne's Grey, a blue/black tone. If you think it out, brown is a
red/green mix....has red/blue/yellow in other words the "normal"
primaries. They always will mix up muddy, which is why press printing
uses CMYK. Adding a blue/black layer seems to counteract this
tendency.....At least for me!

How many of you gum printers use four separations? I have read that the
K carries much of the contrast and therefore screws up colour balance. I
was just wondering who prefers RGB, who prints with CMYK??????

Kate

-----Original Message-----
From: Katharine Thayer [mailto:kthayer@pacifier.com]
Sent: Monday, 5 July 2004 1:25 a.m.
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Gum Tri-Color Yellow

Katharine Thayer wrote:
>
> Ender100@aol.com wrote:
> >
> > I wonder if the muddy brown is an issue not so much of the colors
used, but perhaps poor color seperation in the negatives, or too fine a
screen in the seperate negatives. Larger dots of each color might give
better color rendition, just as it does with inkjet printing and matte
papers.
> >
> > Mark Nelson
>
> Not likely in my opinion. I haven't printed tricolor from continuous
> tone negatives, although Dave has (sorry, I can't think of Dave's last
> name at the moment, but you know, Cowboy Dave) quite successfully; I
> don't remember seeing any brown tones in his tricolor gums. I've
> printed tricolors from many different types and resolutions of digital
> negatives, and I've never seen this brown tone in my own tricolor work
> from beginning to end. So I'm inclined to say it has little to do with
> the negative and much to do with the pigment. The fact that it didn't
> improve for Tom with different curves but it did improve when he
> switched from PV19 to PR209 should be an indication right there (I'm
> assuming he was using the same negatives).
>

This is not to say that I don't believe it's possible for someone to
make really eccentric color separations that create weird color
combinations, but why would anyone do that? Even if their intent was to
create weird color combinations; it seems to me that weird color
combinations can be better (and more cheaply both in time and money for
negative materials) effected by choosing pigments that would create
weird colors in combination with eeach other than by trying different
weird color separations to see what happens, unless it's the
unpredictability that interested one.

Also want to make it clear that I don't think this brownish or
brownish-purply cast has anything to do with how dilute or concentrated
the pigment is. I've printed with pigment concentrations ranging from
totally saturated color to just a whisper of color for each of the
primaries, and have never seen these brownish tones with the pigments I
use; the color combinations are clear and not brown no matter what the
pigment concentration.
Katharine

---
Incoming mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.714 / Virus Database: 470 - Release Date: 2/07/2004
 
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.714 / Virus Database: 470 - Release Date: 2/07/2004