Flattening albumen prints

In my experience, flattening mounted albumen prints can yield a
range of results, from poor to very good.  Among other important
variables, the type of cardstock used for the mount is a key
indicator of potential success. The heavier the mount, the worse the
results tend to be.  Also, there are instances when the mounts are
flattened, only to have the warp reappear over time.  The
re-occurrence of the warp has a lot to do with the display/storage
environment (especially fluctuations in relative humidity) and the
storage materials and techniques used.

Essentially, the technique used to flatten mounted albumen prints is
to humidify the mount with deionized water vapor applied in a
humidity chamber or through Gore-Tex fabric.  Once the boards have
relaxed sufficiently, the photographs are removed from the moist
environment and placed between blotters and under weights to dry and
flatten.  This process can be repeated if required.  Depending on
the nature of the individual photograph and the prerogative of the
conservator, there can be a number of variations on this process.
Also, prints and mounts may require surface cleaning prior to this
treatment.

A photography conservator must balance the potential for a
successful flattening treatment against the fact that exposure to
elevated humidity is likely to cause an increase in the cracking of
the albumen layer which may be perceptible as decreased gloss.
Other risks include cracking brittle boards by applying too much
weight during the flattening step.

Photographs on warped mounts are often displayed (without treatment)
in sink mats which are designed to safely compensates for the warp.

Paul Messier
Conservator of Photographs and Works on Paper
77 Griggs Rd. Brookline, MA 02146
+1 617 738 7072
Fax: +1 617 738 8841

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                   Conservation DistList Instance 9:3
                   Distributed: Monday, June 19, 1995
                        Message Id: cdl-9-3-001
                                  ***