Judy Seigel (jseigel@panix.com)
Thu, 21 Jan 1999 18:38:19 -0500 (EST)
On Thu, 21 Jan 1999, Galina Manikova wrote:
> My experience with dry pigments for gum goes for ceramic pigments, which
> would be actually worse, then any other kind as the particles are very big
> in size. One has to ground the pigment together with some kind of "medium"
> either by hand or in a special ceramic/stone mill before you mix it into the
> emulsion. The medium would be dependent on your further process and the base
> you are applying the emulsion on. For regular gum process I would use some
> kind of acrylic medium. For certain pigments it helps to add a little sugar
> syrup, which would also help to spread the emulsion more evenly before it
> dries on your paper/brush.
I've used dry pigments quite often for gum, and find that -- are you
ready? -- almost none of the "lore" is true. For instance, Scopick gives
an elaborate formula for "plasticizing" the paint. Not only is it not
necessary, it stains very markedly, at least did with my materials.
(Contains, as I recall, glycerine, sugar, Photo-flo, oh lots of whatnot.)
As I commented in P-F #2 (p. 30, "The 'Seems-logical' disease in Gum"),
John Schaefer's "Ansel Adams Guide" copies it from Scopick, also presents
it as gospel, but neither of them can have tried it. The formula,
originally from Ralph Mayer's Artists Handbook, was intended for making
your own watercolor paint, for the veils and washes of thin watercolor. In
gum printing, whatever your colorant -- Sumi ink, dirt, dry pigment, iron
filings, pencil sharpenings, glitter, etc. -- there's going to be a
vehicle of GUM ARABIC. And that will carry the pigment to spread & bind it
to the paper.
Again, as I have noted previously, you yourself cannot grind pigments any
finer than they come from the factory -- and that is *finer* than you
need. The "grinding", however you do it -- palette knife on glass, mortar
and pestle, or as I do, the easy way, with a stiff round pointy oil
painting brush in my regular mixing dish, is simply to be sure all the
pigment particles are surrounded with gum. I have this on authority from
paint manufacturer -- also my own observation.
As for mixing the pigment-in-gum in advance, printers I respect do this,
but I myself have always found it more trouble than it's worth. There is a
tendency for the mixture to solidify, so that stirring is more trouble
than mixing again. The mix is never the exact color and/or concentration I
want for a given operation, and measuring, especially if you change the
thickness to suit, is much harder in premixed than additively.
Reasons for the dry pigment are, of course, economy, but sometimes I want
a really thick opaque coat for a background or covering or some similar
game, and that's much easier to get with the bulk pigment. Incidentally,
the tube paints are much more economical in the 15 ml size, so once you
find your colors, doesn't make sense to buy small, if that's what Dave
meant he had done.... unless I misunderstood.
Of course, having written this, I must note that each combo has its own
kinks, & I daresay ceramic mixes are different -- and since they can't
sink into the paper (which was problem with "plasticizer" noted above, or
one of them), maybe they even like those additives. But for work on paper,
if you're determined to try anyway, I'd suggest not mixing a whole bunch
of any such formula until you've tried it. In this house, there wasn't a
one of them, separately or together, didn't make matters worse.
cheers,
Judy
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