Discolored photographic prints

As a conservator not specialized on photographs, I am asking for
help from colleagues from this profession. I would also be
interested in knowing if this particular problem has occurred in
other museums.

Lately a large number of black and white photographic prints in our
exhibition show a bright orange discoloration.

The prints (on Agfa Multikontrast premium matt 321 PE paper) are
laminated on kappa-board with a so far not identified commercial
adhesive sheet.

The prints had been in the exhibition for 2 years before showing the
discoloration. Prints in display cases have not shown any
discoloration.

The bright orange discoloration has a kind of granular pattern and
is very inhomogeneous (if you would like to see it, I can send
digital images via email). On some prints fingerprints (probably
from the laminating process or from installing them in the
exhibition) are visible. In these areas the print is not
discoloured.

So far, we suspect a reaction with hydrogen peroxide, which is added
to the water of the air conditioning unit servicing the exhibition
gallery. Hydrogen peroxide is added in a very small amount, so only
traces would be found in the air. Also, the same additive is used in
other air conditioning units throughout our and other museums, where
no discolorations of photographs have been detected.

I would appreciate any information on possible factors causing the
discoloration and any ideas on how to prevent something like this to
happen to new prints in the future.

Leonie Gartner
Staatliche Museen zu Berlin SPK
Ethnologisches Musem
Arnimallee 27
14195 Berlin
+49 30 8301 338


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                  Conservation DistList Instance 20:30
                 Distributed: Friday, December 1, 2006
                       Message Id: cdl-20-30-015
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