Re: oil printing
Sorry to barge in here, but I'm having trouble following this
conversation. Dirk asked a question about why there's no hardener in
the gelatin layer, and since the subject line is "oil printing" I
assumed he was asking about the gelatin layer in oil printing. But
the answer that came back seemed to be about the gelatin layer that
acts as a size for gum printing, which I, for one, found quite
confusing.
On the chance that I had it right in the first place and the question
was about oil printing, the answer is that there's no hardener in the
gelatin because in oil printing you don't want the gelatin to be
hardened as a whole layer, as you would if you were using the gelatin
as a size for gum printing. You only want the gelatin hardened where
it's exposed; that's the purpose of the dichromate. Just like you
wouldn't put a hardener in the gum that you're using for a gum print,
because you don't want *all* of the gum hardened, just the gum that's
exposed. Hope that's the question you were wondering about..
If I was wrong and the question really was about sizing for gum
printing, then I might suggest that it can be helpful to change the
subject line if the subject changes, so people trying to follow the
thread can make sense of it. Thanks,
Oh, and by the way, while we're confusing the two issues: part of
the answer about sizing for gum printing seemed to suggest that if
the glyoxal were mixed into the gelatin before being applied,
rinsing might not remedy the yellowing problem. In my experience,
that's not a worry. I apply the gelatin with the glyoxal mixed in,
and rinsing does remove the yellow, in fact I don't bother to rinse
separately after sizing, because though the sized paper does turn
yellow in a few days, it returns to pure sparkling white in the
development phase of gum printing. So I don't find any need for a
separate rinse. There, now I've given you an answer for either
possible meaning of your question. :--)
By the way, I enjoyed seeing your prints, and noticed that you took a
workshop from Kees. Look forward to seeing your progress,
Katharine
On Sep 24, 2008, at 11:52 PM, Dirk-Jan Treffers wrote:
Judy,
Just a wondering thought: Is it on purpose that you omit the use of
hardener in your gelatine layer? I also found more or less the same
recipe on alternativephotogrphy.com, and there also the use of a
hardening agent like glyoxal wasn't mentioned.
Is that correct, and if so, what's the reason for that?
And another question (you see, I'm curious)... why is that in
oilprinting, a negative is used, while in the gumoil process (which
sounds more or less the same...) you need a positive....
thanks already!
DJ
2008/9/25 Judy Seigel <jseigel@panix.com>
On Wed, 24 Sep 2008, henk thijs wrote:
OILPRINTING is a contact-procedee like gum, cyano etc..
Coating a 300grams paper -like you use for gum- with a 10%
gelatine, three times, let dry and coat with a 6% potassium
dichromate.
Like gum, put the neg on top , UV-light for twice the time you
expose gum.
Wash out the chromate, gelatine is partly harded and now you have
your matrix for oiling.
Info about the ins and outs are difficult to find; in David's book,
the chapter about oilprinting is a bit thin. I had to do a lot of
testing (or better: paperbasket filling with rubbish) before making
oilprints ; but if you succeed there is no need for a darkroom
anymore (and if you have anyway a suitable negative and some
chromate ....).
The books and magazines of Demachy's period when oil printing hove
into view have many articles about that process, some, I daresay
quite complete.
I found them appealing, but resisted for a number of reasons,
including and especially because I'm allergic to the solvents (and
warn anyone using oil paints be careful: Turpentine is one of the
two most allergenic substances for humans. The other is chrome, tho
I don't know if that extends to all forms, including dichromates,
or just shiny bumpers.)
In any event don't get your hands in the turp, or yr feet either
for that matter... I now use odorless mineral spirits when the need
arises -- tho some labelled "odorless" lie -- so far OK, but I'm
careful, ie, don't leave the stuff in an open container, and if I
have it on rags or whatever, dispose of them in a closed container
in another room... etc.) The worst, probably, is in a classroom --
imagine 30 palettes or trays in an enclosed space wet with
turpentine !!!! (Yeah, in the good old days.)
Meanwhile, I'll check some of those period annuals, or whatever I
find in the Mississippi delta AKA my book shelves. Or aren't there
indexes of that literature somewhere?
PS to Henk: Sorry I can't join in the chorus of praise, because I
have to switch partitions before I can see those prints... gotta
get myself into giraffe, or whatever it is...
But soon, I hope....
J.
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