> size the paper once or twice before you use it? Do you harden it once or
> twice? Also- how long does a hardening bath last? Is it best to mix up
>
The only one of those questions I can answer definitively is that the
hardening bath lasts forever -- it's a preservative. If it gets thick
with paper fiber, filter it & good as new again.
Sizing paper once or twice (or nonce) takes us into the realm of personal
preference -- or myth. Gini posts that she sizes twice -- & she's clearly
making gum toe the line (to mix metaphors). Gini: do you formaldehyde
once or twice? I would ASSUME twice, because the first coat of
gelatine possibly might could dissolve off in the 2nd warm gelatine bath
if it weren't hardened.
I myself prefer a lighter size, on some papers only mixing it 3/4
strength, because they get too brittle & curly. If it needs more size in
work, I'll add a coat later. I would also suggest that if you're using
BFK don't bother with a 2nd size until you're getting results -- & then
only if needed. That's an awful lot of work to throw out! (MANY papers,
by the way, will give you one free shot -- a good first coat without
added size. Other papers, such as Stonehenge, and a Lana I just tried,
won't do gum, period.)
the hardening bath in a small quantity and paint it on, or mix up a liter
> and re-use it? I believe I compounded my hardener 20ml Formaldehyde to 1000ml
> water.
>
Incidentally, there's a good book that as I recall describes the sizing
process quite well -- David Scopick's "The Gum Bichromate Book" -- but the
first edition only, a simple, clear, unassuming little manual. His 2nd edition
added all kinds of bells & whistles & frankly I didn't understand stuff
I'd been teaching for 10 years!
Anyway, harden outdoors: the formaldehyde is wicked. Mix up a liter, pile
in your sheets 1 at a time, turning each over to be sure no bubbles, then
when all are in (or in a few minutes) turn stack over & pull out, starting
with the 1st in, hang to dry OUTDOORS. And, as I said, save the working
solution forever, replenishing as necessary. 20ml per litre is ballpark --
I use 15, but who knows?
> also let them set a little too long probably. I began printing a couple
> of hours after they were dry. And it was HOT in the room, and humid. More
That "couple of hours" could be the problem all by itself if you're using
saturated solution of sensitizer
in warm weather. I was taught use the emulsion within 10 MINUTES and
expose the print within 20 minutes! In cool dry weather you can stretch
it, also with weaker concentration of sensitizer it doesn't cook so
quick. When Carson made the comment about heat & humidity I tested an
extra 15 minutes -- it did make a difference.
(Carson: are you reading this? The day the weather got hot &
humid I found my flash DID fog, instead of extending the range!)
> It seems I need to change more than a few
> things in order to get a mildly acceptable print. I'm surprised that BFK
> works at all without a size- I've never heard this from anyone else (another
I would STRONGLY suggest you do some (more?) reading . Gum isn't a simple
cut-and-dried process like, say, platinum printing, where you can get some
formulas & instructions & sweat a while & have at least the gist of it. I
mean not necessarily.(Puyo, by the way, totally sneers at added sizing!)
I myself find the gum literature of yore especially
endearing. Gum printers were (still are of course) adorable. See if
you can get the Bostick & Sullivan gum tech pack (from the old
PhotoMiniature). See if your library has Paul Anderson's Pictorial
Photography (title something like that) which has good chapter on gum;
Anderson also has good chapter in Dudley & Henney (Henney & Dudley?).
Crawford's gum chapter is good. Robert Demachy wrote a charming essay on
gum printing reprinted in English by Peter Bunnell in a book titled, as I
recall "Non-Silver Processes," late '70s. You said you'd read Luis
Nadeau's book on gum. That's a good one to read again. I recall particulars
there I'd never seen anywhere else, & I daresay also an
extensive bibliography.
You will note, BTW, how different some of these are from each other.
Proving what Stieglitz wrote: there is no such thing as "gum." Each print
& printer is sui generis. (I found an article by Stieglitz to that effect
in a photo magazine of the '20s or maybe late teens, was so enchanted I
put it in a VERY safe place, and have never been able to locate it again!)
Well, keep us posted.
Judy