From: Richard Urmonas (rurmonas@tpg.com.au)
Date: 08/20/03-03:45:54 PM Z
On Wed, 20 Aug 2003 04:01 pm, you wrote:
> 1. I don't want to store/mix (mess in other words) with pure silver
> nitrate and will have the 12% solution prepared by a chemical supplies
> store - will purchase it bulk and use when necessary. I remember reading
> about preservatives that should be added to the silver nitrate solution
> (citric acid?). What I didn't understand: Is this practice necessary to
> preserve the silver nitrate solution itself or to preserve the
> sensitized salted paper (to expose... say... one day after sensitizing)?
> I'm confused...
Generally the citric acid is used to preserve the salted paper when
sensitised. Do not add it to the bottle of silver nitrate solution as it
will shorten the life inside the bottle. The organic compounds in
the citric acid will allow the silver nitrate to react to light more readily.
I once mixed some citric and silver nitrate in a batch and tried
to store it. It lasted less than two months, even in brown glass,
and dark storage.
I would recommend against storing silver nitrate in solution for long
periods of time. If you will use the batch you buy in say 6 months
then OK. If it will take longer, I would get smaller batches. While
pure silver nitrate solution in brown glass + dark storage should
last a long time, the "photo grade" has some impurities which seem
to limit the life.
While silver nitrate is a dangerous chemical, mixing the dry crystals
into a solution is a fairly safe operation if you take sensible
precautions (rubber gloves, eye protection, work over newspaper).
It is probably no more dangerous than working with the solution.
> 2. Is there anyone who printed on unsized Canson Montval 300gsm? If yes,
> did you like the result? (I don't want muddy, flat prints) I have read a
> poster (in photo.net) praising unsized (I mean extra sizing) Fabriano
> Artistico...
I think you will need to experiment with some papers yourself. Salted paper
seems to work well with a many papers. Muddy prints sound like the negative
was too low in contrast. The typical paper related problems are highlight
and border staining, difficulty in even coating, and coating soaking into the
paper too far. I have not done any salted paper in a while, so cannot
recommend any papers.
Richard
--- Richard Urmonas
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