[pure-silver] Re: Oh How I Miss This Paper


----- Original Message ----- From: "richard lahrson" <gtripspud@xxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Thursday, January 27, 2011 1:09 PM
Subject: [pure-silver] Re: Oh How I Miss This Paper


Hi!

     Even if the paper is old and fogged, can't this
be cleaned up?  I'm thinking of more restrainer.
                                              Best, Rich

Its possible to salvage some paper using fairly strong benzotriazole but there is a limit. At some point the speed and characteristic of the paper is just compromised too much. Fog mostly comes from a very slow continuation of the "ripening" process the emulsion goes through during manufacture. Some halide particles become developable even though not exposed. To some degree restrainer can prevent them from being developed, and restrainer and anti-fogging agents are added to the emulsion for this purpose as are chemicals intended to prevent or slow the fogging process. However, we are talking about paper which has not been manufactured for more than ten years and some may be decades old. While it may be possible to make prints on it the paper will not look it did when new. Paper and film is perishable. If kept in frozen storage it may last a very long time but at normal room temperature the life is pretty limited. Opened packages fog quite fast, perhaps because of the effect of oxidation. Benzotriazole is more a more effective anti-foggant under most conditions than bromide and has less effect on speed.

--
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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