arcane gum research, beware

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From: Christina Z. Anderson (zphoto@montana.net)
Date: 07/09/03-07:42:20 AM Z


Dear Group,

     I just CAN'T help myself!!! I'll have to go to Arcane Books Anonymous!

I went to the rare books place in Mpls again (the airport is in Mpls, had to
pick up hubby, so in order to make a 300 round trip drive worth it...) and
just have to share from my bounty. Beginners, shield your eyes!
Inveterates, humor me! If info has been previously posted, then hit delete.

More Demachy notes:

1) (I detect a little French/English competition here...) Demachy thought
powdered pigments were useless extra work, abandoned them and used tube
pigments always, for the "last 11 years" he says in this article. He crits
the English for using powdered pigments, can't understand why all that
grinding and mess, and says the French all use tube pigments and their work
is beautiful (Bremard, Puyo, Grimprel, Hahette, Sollet, Le Begue, Laguarde)
He says honey and glycerine present in tube pigment has no effect on the
gum, proven by the quality of the work of these artists.

2) In this source he says he uses a 50% gum solution! I gum to 1 water!

3) Demachy calls sizing paper tedious. He says (!), "Another tedious
practice which is generally recommended and that I have never found it
necessary to use, is the preliminary sizing of the paper. I don't know if
it is because the proportion of gum in my sensitive mixture is higher, or
because my gum is less acid than usual, but I have never experienced the
difficulty in getting pure high-lights at will that many gum experts
complain of-though I never give any additional sizing to any paper. The
Canson papers (aquarelle et lavis), the Joynson, Turkey Mill, Michallet,
Ingres, Lalanne, Rives, Tochon Lepage, Dambricourt papers have always proved
quite satisfactory. Even the Van Gelder papers, which are very poorly
sized, work well just as they are." .

4) Further from Demachy: "On the other hand I find that not enough has
been said of the exaggerated acidity of gum solution. Many failures
ascribed to insufficient sizing, false proportions or wrong exposure have no
other cause. When a gum solution begins to get stale-and this may happen in
a few days or a few weeks according to circumstances,--its normal thickness
or viscosity diminishes proportionately to its growing degree of acidity,
and it loses its solubility in equal proportion. Result:--a much thinner
sensitive mixture,--a different style of coating, a strong tendency towards
granularity, staining of the whites, and a sunken-in, dirty appearance of
the final print. Watch your gum solution, test it now and then with
bicarbonate of soda and if the effervescence is marked, throw half of the
stock solution away and add equal quantity of fresh solution at 50%. You
will be surprised at the difference in the results."

     I tell ya, it's in the acidity and alkalinity!
     With lemon juice I got steps printed all the way up to the 21, which as
Sandy says is attributable to lowered contrast, or, as Demachy was
recommending its use in the first place, for "stability to the midtones" or
insolubility of gum without exposure. Would work great where you need
fogging, flashing, or a thin layer of color or tone. Isn't particularly
necessary in my practice, because to me it looks like stain. It smooths the
contrast throughout the steps, from maximum black on up (unlike straight di
where you get clearly defined steps).
   If you want to poo poo the size info above and say Demachy only did one
coats so the initial size in paper was sufficient, yes he only did
monochromes but not only one coats, although he was renowned for being able
to pull off a fully tonal one coat in a number of sources I have read.

AND, I was able to look through original Camera Work Magazines with
photogravure (?) inserts. Incredible. But I have to say that Demachy's
work was not just good because of technique. Even though I don't like a lot
of the romantic imagery from the time--including the personification of
virtues by posed people, Demachy's content is actually quite a step above
his era, so I think the reason even non-pictorial photographers didn't
criticize him is not just due to his perfected gum process. And to think he
only did gum for a decade or so, giving it up for the oil print....

Have a good morning! If I get up enough nerve, I might even share a very
unique method of gum printing patented in the early part of the
cetury...last century, that is. And maybe next week, after Melvin's gum
info unveiled at APIS, all our processes will become arcane.
Chris


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