From: Judy Seigel (jseigel@panix.com)
Date: 03/20/03-01:29:05 AM Z
On Mon, 17 Mar 2003, Christina Z. Anderson wrote:
> Demachy back in 1898 said stain was caused by using too little gum. In
> essence, the gum keeps the pigment suspended above the paper so it doesn't
> have a chance to sink into the fibers. This is true, too, of
> watercolorists, who use gum arabic to allow lift off of paint.
If it doesn't connect with the fibers at least a little it's not going to
work. But in any event Demachy was working on paper without an added
size... we rarely do.
> Demachy also said that too much sensitizer in the mix dilutes it to an
> undesirable consistency so that it is able to sink in, causing staining.
Demachy was a remarkable trail blazer, and got a lot of it amazingly right
-- but I'd make the analogy with Sigmund Freud... Remarkable trail blazer
but not right in every particular for all time.
> got both in the Z process, but in deference to Z, I was using one of the
> most staining pigments, quinacridone violet.
Is your QV a paint? If so which one? Or a dry pigment? I find it
doesn't stain in paint (either Rowney or DS, I forget which) any more than
thalo, quinacridone red, or any of the ones you cite -- which do not stain
AT ALL here .... honest.
> .... Or, throw caution to the wind
> and just assume that you need less of the staining pigments (carmine, lamp
> black, perinone orange, permanent red, perylene Maroon, thalos, q violet,
> etc.). Luckily the staining colors are intense enough that a little goes a
> long way. But staining pigments will stain if not enough gum is used, or if
> too much dichromate dilutes the solution so the paint particles hit the
> paper and sink in.
Any pigment that stains even a little will stain proportionately more as
more of it is used... I haven't used all these pigments, and again you
don't state brand (which is crucial, because the additives as well as the
manufacture vary), but I find no staining AT ALL with DS or Rowney
perylene maroon, thalo or carmine. Carmine incidentally is a divine
intense luscious color, but usually less archival than the others -- the
giveaway is that it's now called "permanent carmine." As soon as they put
"permanent" in a name you know it's less archival than the others.
Of the others you name I've not tried the orange, or the "permanent red"
(what pigment is that? AFAIK that's a name, not a pigment), and the only
one of them I've had stain is the lamp black.
> Furthermore, Hilary Page says:
> mediums... stain more as they contain more glycerine."
Again, she's not talking about gum printing, but watercolor... tho if that
statement is true for gum, could be why Skopick's medium suppoedly for dry
pigment stained so badly... it had glycerine.
> ...my plastic *teaspoons* were stained with
> quinacridone violet! :)
That still doesn't prove anything for paper -- plastic my react
differently... again, however, you don't say if that was a tube paint or
pigment, and which brand.
> Acidity of gum.
I doubt acidity of gum is a factor in staining... unless you mean less
acid more staining, because the Pictorialists often recommended letting
the gum sour... I myself found no correlation of any factors with
"acidity" of gum, although admittedly my acid-ometer was subnormal.
> ... Humidity of your sensitizer (both acidity and humidity according to
> Kosar affect exposure, and I think deserve a closer look if someone wants to
> do some testing with me of ammonia and lemon juice side by side added to
> sensitizer or coated on the paper and dried. AND exposing wet paper. Kosar
> In regards to below, Judy, I think it may be backwards from what you
> say. Most of the staining colors are the new synthetic organics--thalos,
> quinacridones, vat pigments, dioxazines, pyrroles. They are small
> particled. The quinacridones are favored by the auto industry because they
> have small particle sizes. Not developed commercially until 1958 (p. 80
> Page).
Nope -- not backwards around here... It's not clear to me whether you
found this from testing or are quoting Hilary Page, who (as I noted) is
writing about watercolor process not gum printing. Are you saying that you
got staining with quinacridone red? With thalo blue? What brand? I often
use both so strong they're too strong -- and no staining. They are the
LEAST staining colors -- in NYC.
really,
Judy
> <Judy says>
> christina... strangely or not, the "staining" category doesn't apply to
> gum printing, or not that I've ever been able to detect.
>
> I'd already noticed lack of connection with the manufacturer's designation
> in my own printing -- I've found that *staining* when it happens is
> due to some dumb mistake -- old emulsion, too hot, too humid, bad paper,
> bad size -- or like that. But the explanation from the W-N lady of those
> categories in *watercolor painting* was as I recall that the stainers are
> colors made from the old mineral pigments. The particles are fairly large
> and irregular & roll around and get stuck in the paper fibers. The
> non-staining are the new synthetic colors with much finer particles,
> "almost like dye."
> But we don't get a lot of correlation of gum behavior with watercolor
> behavior (that was the false premise of Scopick's "medium" for dry
> pigment). In watercolor, the paint is thinned I mean really *thinned* with
> water until it's just the palest tint.... and the gum arabic in those
> veils and washes is almost non existent. In gum printing, even in the
> zimmerman process, a much more robust paint-gum mix is used. The half
> tones and highlights are achieved by removing the unhardened part, not by
> thinning the paint with water. So even with little or no gum added as in
> Zimmerman, the pigment remains embedded in gum.
>
>
>
>
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