>Possibly museums or university departments with an interest in conservation
>would have this equipment - I'm sure there are people on this list who would
>have more idea than me about it.
There are mainly 3 types of accelerated ageing procedures.
1-Light fastness. I.e., resistance to UV radiation and light
2-Heat & humidity
3-Oxidizing gases. Resistance to pollutants
Silver systems will be subjected to 2 and 3 above. 1 and 2 will apply to
color materials. There are many ANSI, ISO and BWS standards covering this.
Wilhelm's _The Permanence and Care of Color Photographs_ has a review of
them.
For many years when I was looking for permanent pigments, I used a simple
set up with fluorescent lights that were left on 24 hours a day. They were
quite effective. I'd make a step wedge with the carbon process, and cut it
in half lengthwise. One half was kept in the dark as a control strip and
the other one was mounted about 1 cm away from the fluorescent tubes. Some
"permanent" pigments would lose 50 % of their density in a matter of
days... Others showed no changes after 6 months.
I used a reflection densitometer to plot the changes but the control strip
is all that is really required for anyone who wants to do the same kind of
test. You can use sunlight exposure behind a window but these are
conditions that will never be repeatable.
Luis Nadeau
NADEAUL@NBNET.NB.CA
Fredericton, New Brunswick, Canada
http://www3.nbnet.nb.ca/nadeaul/