Testing AGFA yellow silver foil

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Invitation to a users' test: Detection of harmful atmospheres for
photographs in archives and museums with yellow colloidal silver
foils.

Prof. Loebach from the University of Applied Sciences Cologne,
Germany, Department of Imaging and Media Technology, wants to carry
out a broad test with the AGFA yellow silver foil. This foil
contains a suspension of yellow colloidal silver on a polyester
base. The foil is used in the Photographic Activity Test for
enclosures too. The yellow silver acts as a very sensitive detector
for harmful atmospheres. If the silver is oxidized, and sometimes
reduced after the oxidation, a change from yellow to orange or
reddish colors occurs. This change can be measured with a
densitometer as a loss or increase in blue density. The test period
is envisaged for two years. The participants are requested to send
the foils back every half year for evaluation. There are no fees for
the test.

    Prof. Dr. Wilfried Loebach
    Fachhochschule Koeln
    FB-Photoingenieurwesen
    Betzdorfer Strasse 2
    D-50679 Koeln
    wloebach [at] gauss__fo__fh-koeln__de
    +49 221 8275 2531 (12)
    Fax: +49 221 8275 2836

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                  Conservation DistList Instance 12:76
                  Distributed: Friday, March 26, 1999
                       Message Id: cdl-12-76-015
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