From: Katharine Thayer (kthayer@pacifier.com)
Date: 09/01/03-11:16:01 AM Z
Gary Nored wrote:
>
> Having made my first acceptable single-coat gum print a
> few weeks earlier with out local alt-process group, I boldly
> decided to take the process home and start playing with
> it. I used the same paper (Fabriano Artistico), the same
> Windsor Newton lamp black water color paint and a
> saturated solution of ammonium dichromate in the same
> proportions as before.
>
> The first prints were terrible -- kinda like Ed Buffaloe's
> famous black prints, but with some hint of image. I
> thought the problem might be "staining" so I decided to
> try sizing the paper with gum arabic.
>
> I coated several sheets of paper with gum/dichromate
> solution, omitting the ink. To my surprise, this paper
> didn't come out white after exposing to sun and washing --
> it comes out a nice caramel-brown color. Further
> experiments yielded nice photograms of white and brown
> (better than the prints with pigment in them).
>
> So now I have a zillion questions. A few of them are:
>
> Is the gum itself supposed to turn brown like that?
It's the dichromate that's turning brown, not the gum. The color can be
cleared by treating the paper with a clearing agent such as sodium
bisulfite or potassium metabisulfite.
>
> Is there a way of hardening the gum without creating the
> brown color?
Not really. Gum will "harden" if left out in the air, but it's not
really permanently hardened; it will redissolve if it gets wet.
>
> Is printer's gum suitable for sizing paper?
I don't think it's a question of printers' gum or another gum; the
question at issue is, is dichromated gum arabic a good size? This is a
question of individual preference. There are a few gum printers who size
with gum, but most of us don't. There's first that brown or tan color
that needs to be cleared, another step in a process that has enough
steps to start with. Then there's the extra dichromate that one would be
using, and the toxic waste questions (that bother some of us more than
others) that might attend the use of extra dichromate.
(I used Varn's
> 14 Baume 100% Gum Arabic solution which I bought at a
> printer's supply house.)
>
> For that matter, is printer's gum really suitable for making
> gum prints?
This is a controversial question. Many gum printers would say yes, but I
would say it depends on what kind of look you're after. Some of us who
print very transparently find that a dark gum can darken the colors
enough to be unacceptable. Others say it doesn't matter. It's your call.
Katharine Thayer
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