Discussion in 'B&W: Film, Paper, Chemistry' started by jnanian, May 9, 2009.
is it possible to MAKE a (rc) paper "silver out" ?
what is it caused by ?
John, if you're referring to the "silvering out" appearance in antique prints, it is due to degradation of the image from long-term exposure to atmospheric contaminants. Not easy to duplicate, at least not in our lifetimes. There may be some other means of creating that look, but I'm not aware of it.
I think there is a toner that produces a metallic silver look to the image. Not sure the name of it, though.
i had made some rc prints years ago and within a year of making them
they seemed to have that same appearance ... no one was a heavy smoker,
the prints were not in a factory or contaminated atmosphere.
maybe it was something else, and not what i was told ... but it did have the appearance
that part of the print had somehow converted to a metallic surface - sheen.
it was kind of weird and i kind of liked it
maybe i can find a toner that will do the same sort of look ...
thanks for the info!
I just posted some information related to this in another thread:
Okay, yes, I've seen that happen with RC prints too, kind of a metallic bronzing that is more or less visible depending on how light hits it. Beats me - there are a lot of people weighing in on this forum that know more about the properties, chemistry and longevity of RC prints than I do. I really only use it for contact proofs and quick test prints.
Rockland Colloids make a Toner called Halo Chrome that gives a mirror like finish to a B&W print. I've never used it but it's been around since at least the mid 70's when I last bought from them. This will most like be the tone Photone is thinking of.
ian and phototone,
I recommend you to read this document that I have added to the Books section of the Links section of APUG:
PHOTOGRAPHS FROM THE 19th CENTURY: A process identification guide
By William E. Leyshon
Book section of APUG:
Scroll down in the book section and click on the link to find it.
There is a reference to these issues with silvering and also some literature references for some further reading.
The Image Permanence Institute developed a test for stability against plating out (or the 'red spot' problem in microfilms) which involved controlled exposure to hydrogen peroxide fumes. To make the test reproducible they had to go to some lengths to ensure a uniform H2O2 fume density, but the basic idea was to suspend the print/film over paper dampened with a peroxide solution.
Plating out happens when an oxidant turns some of the image silver into silver ions. These migrate to the surface of the emulsion and are reduced back to silver again. If you want to play with standard photographic solutions a weak bleach solution would do the oxidation for you, which could be followed up by a residual silver test to re-form the silver, but you need to find a way to stop the silver migrating out of the emulsion altogether.
FWIW, I've found that all my prints made on Foma VC RC paper and stuffed in cheap frames (the sort you can get for $5 at CVS or Walgreens) silver out within 1-2 years. I've used various fixers, but mostly TF-3. Prints made and framed in exactly the same way on Agfa VC RC paper haven't silvered out on me, even after ~5 years. (That's as long as I've been doing B&W printing, so I have no longer-term tests.) Prints made on the Foma paper and stored loose in envelopes or boxes haven't silvered out on me; just the framed prints have done so.
All that said, I'm the only person I've seen who's reported this Foma-specific problem on APUG, so it's entirely possible the problem is an interaction of the Foma material with something specific to me -- chemicals in my wash water, peculiarities of (perhaps improper) processing on my part, trace chemicals in the air in my house, etc. If you're willing to wait 2 years for the silvered-out effect, though, and if you're willing to live with the probability that it will get worse and worse after that, you could try the Foma materials and see what happens....
It's not Foma-specific - as I recall, Ctein ran his tests on Agfa MCP, and the untreated print areas in his framed sample silvered out gloriously. The framing is evidently part of it, but beyond that we don't know why it doesn't happen consistently.
So how to produce the effect consistently and more or less reproducibly, and to stabilize the resulting image once you've got it, is an interesting question.
The MSDS for Rockland Halo-Chrome shows the part 1 ingredients as just ammonium and sodium hydroxide and the part 2 ingredient as cupric chloride.
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