"Louis XVI was gelatined during the French Revolution."
On Mon, 18 Mar 1996, Risa S. Horowitz wrote:
> I use 300 BFK (great tooth to it - from what I hear this type of tooth is
> necessary for anything, the gel, gum, dichromate, pigments to "stick") and
Not true. You can make fine gum prints on kid finish paper, I've done
them on typing paper (one coat). But that's one of the reasons for the
myth about gum not doing fine detail. With "great tooth" each "tooth" is
the size of any fine detail you've got, hence obscures it. For detail, use a
smoother paper.
> Then i give formaldehyde (which I'd like to avoid in the future).
>
Glyoxal works better. Read the archive.
> from here, I was taught (no books, just a photocopied list of recipes from
> Jack Dale at York University and his 30-40 odd years experience with gum
> printing to guide) to use an equal amount of gum arabic and amonium
> dichromate solution (1:1) with my choice (lightest to darkest) of powdered
> pigment (I have a huge list of wieghts for powdered pigments).
Varying the proportion of gum to sensitizer varies the contrast. Anywhere
from 2 parts gum to 1 part sensitizer to 1 part gum to 2 parts sensitizer
is standard gum practice, though it's possible to go to even greater
differentials. With all other variables the same, intensity of pigment,
etc. the higher the proportion of sensitizer, the flatter the contrast,
though with more sensitizer naturally the "speed" of the emulsion is
faster, so you expose less.
> I have read (Bea Nettles I think) that a launderers canned starch can be
> used to "size" paper, and that this must be reapplied once for each
This is a "fact" in all the books, so don't feel bad about it. Not your
fault. However, spray starch not only goes off in color with age, it *in
my experience* can give your print measles. Ginni, are you there? She
uses it successfully, she claims, but I have NEVER found spray starch to
improve a print. A boiled cornstarch size, as in the classic books, works
with SOME papers, but not most.
And note that different colors have different speeds..... Not just from
warm to cool or red to blue, but also in response to the pigment substance
itself. For that matter, *nominally* the same pigment (ie, "ultramarine
blue") from different manufacturers will also be quite different.
Oh, and by the way -- there's a lot on gum printing in the archive.
Cheers,
Judy