U of S | Mailing List Archive | alt-photo-process-l | Re: can't get green tone in gum--help please

Re: can't get green tone in gum--help please

Okay, without further information I'm going to go ahead and speculate
that the tablecloth is blue, and if so, I'll diagnose this
tentatively as a problem of balance: too much blue and/or too little
yellow. I'd agree with Keith that you can't really be sure until
you've got all the colors down, because colors will fool you, but
still, if the overall cast of your print after laying down the blue
and yellow is cyan rather than green, I think it's more than likely
that your yellow is being drowned out by the blue. This is more
likely to happen with pthalo, but I suppose it could happen with any
blue including ultramarine. And I disagree with Marek about the
ultramarine; I get beautiful greens with ultramarine, and don't much
care for the greens made with pthalo, but of course that depends on
what your other colors are too.

A knowledge of the color wheel helps me know if my colors are
properly balanced while I'm printing; after two layers the overall
color cast should be the complement of the third (last) color. I
print in an opposite order than you: yellow, red, blue, so I'm more
familiar with the orange/blue complement pairs than with the green/
red complements. When I was printing in PY110, PR 175, and
ultramarine, my print was always a certain orange after the first two
layers, that represented the complement of the ultramarine, ensuring
neutrals where neutrals needed to be in the final print. You haven't
indicated what your magenta pigment is, which makes it difficult to
say which green cast your print should have after the first two
layers, but green it should be. If your magenta is a blue-ish rose
like quinacridone rose (PV19 gamma) then the green should lean toward
the yellow side (but not too far) if a redder or yellower red, then
it should lean toward the blue side.

Hope any of that is helpful,

On Mar 10, 2009, at 11:25 AM, Katharine Thayer wrote:

Charles, if the tablecloth isn't green, what color is it?

On Mar 10, 2009, at 9:47 AM, Charles Ryberg wrote:

Folks, I've made one nice tri-color gum (many months ago)
and thrown away scores. The image I'm trying to print is a café
scene with green only in the tablecloth. The rest of the image is
warm--mostly pale cream yellows and red brick. There is a woman
in a blue dress walking away from the camera. I like the image.
My first coat is Daniel Smith French Ultramarine. The second is
Daniel Smith Hansa Yellow Medium. I have not yet done the
Magenta. The overall cast of the image is clearly cyan though
there is yellow too. But no green. When it dries, I'll do the
magenta, but I just can't see the image working without that small
green cloth. Any advice?