Re: Gum problem(s)

From: Christina Z. Anderson ^lt;>
Date: 11/18/05-08:27:14 AM Z
Message-id: <006201c5ec4c$c4811270$6b6992d8@christinsh8zpi>

> I notice that the pigment/gum in the area outside the step tablet was
> extremely soft and I removed it all by rubbing my finger as delicately as
> I
> could. I assume I shouldn't do that in the future. One may say that's very
> good, you got 7 to 9 steps showing to which I would reply the separation
> between those step is close to inexistant and we can hardly read the
> number
> or text because of the texture and staining.. If this was a delicate
> flower
> with lovely details, only my imagination could tell and this is certainly
> not what I was expecting but I also saw in my reading that this could be
> helped by printing multiple time. Assuming the pigments don't get into the
> paper the texture would possibly improve as well.
> Yves

I, too, like Judy I think, can get easily 4-5 stops out of gum (unlike salt
printing, for instance, where one can get probably 10 stops).

My exposures under UVBL are 6 minutes. Even 6 minutes is plenty. I am
using diginegs.
I, too, use Fabriano, but I size it.

I am thinking my ratios are about like yours except I don't use photoflo,
and i use tube pigment. Photoflo is a surfactant that might make your
pigment sink into the paper more easily?

If you are using analog negs, then I could maybe understand a 6 minute
exposure, but 20 seems excessive with digital. One way to tell if the
exposure is excessive is to leave the test strip soak for a day and brush
it, and if it still doesn't clear, then you might have excessively exposed
the emulsion or baked it on with the heat from the sun lamp.

If your test strip is nicely exposed, without a lot of blocking at the dark
end, and your numbers are obliterated, then suspect the pigment has entered
the paper fibers and stained. Sizing will alleviate that.

BTW, the idea that the dichromate may, in fact, expose the layer at the
bottom (I wouldn't have a clue if it did or not) probably stems from the
observation that when you first soak your paper in the water face up, all
the dichromate leaches out immediately. This only takes about a minute to
happen, and then you can lift the print out of the water and watch the
dichromate stream off. The layer is still perfectly intact. I have no idea
chemically why this is so--the chemists of the list can answer that one--but
I have observed sometimes in coating a paper with magenta that in my brush
strokes the yellow of the dichromate brushes at the paper base and the
pigment seems to be on top, so perhaps the dichromate is of a different
weight or whatever the term is chemists use...mole...blah blah..

Happy gumming, keep it up, one more convert yea!!
Received on Fri Nov 18 08:31:48 2005

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