Re: Saving old negatives

----- Original Message -----
From: <Irvingyoung2@aol.com>
To: <alt-photo-process-l@usask.ca>
Sent: Wednesday, April 05, 2006 10:52 AM
Subject: Saving old negatives

>I realise that this enquiry is not in the direct thread of
>alt processes but
> I'm hoping that someone out there can help me. I have a
> fairly large number of
> old glass negatives, these are in the region of 100 years
> old(No, I didn't
> take them myself). The problem I'm having is with
> "silvering" of the image.
> I have tried using a proprietary tarnish remover on
> a few with some
> success, but am a little nervous of subjecting the rest of
> them to the same
> treatment. What I would appreciate is any advice on
> restoring these negs without
> risking irreversible damage.
>
> Irving Young, Lancashire, UK.
>

   This is a common problem. I agree with the advice to talk
to a conservationist before taking any action other than
scanning. You may be interested in a paper available from
the Conservation On Line site specifically on this problem.
Its at:
http://palimpsest.stanford.edu/byauth/dipietro/mirroring/

   Mirroring is due to a redox process where the image
silver is oxidized to very fine silver oxide by oxidizers in
the atmosphere, migrates to the surface of the emulsion, and
is then reduced to metallic silver by other atmospheric
polutants. The surface silver can be removed using a very
mild bleach but the damage to the image can not be reversed
because some of the silver has been removed. The important
thing is not to use any treatment until determining whether
it may further damage the images.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com