White haze on photograph

The photograph which I'm working on, is a resin-coated color
photograph, that was stuck with its emulsion of gelatine on the
glassplate of its frame. Where the gelatine was adhered to the
glass, it wasn't anymore adhered to the paper base of the
photograph.

Because the photograph wouldn't come off the glass by locally
moistening the emulsion, we decided to soak it off by putting it in
a bath with water and 1/200 Agepon. After 7 hours of soaking, the
photograph was released. Immediately, the emulsion was glued
together with the paper basei, using a combination of wheat starch
paste and methylcellulose, while the object was still wet. After the
glued photograph was dried, between two sheets of hollytex and
blotting paper, there was an unidentified white haze noticeable on
the surface of the picture, around the edges of the tear. This haze
is not mechanical damage, nor is it mold. Could it be barium
sulphate that has penetrated the colour surface? Are there other
possibilities? If this is barium sulphate, how can it be determined
and how can it be removed?

Beside this haze, there is a noticeable change to the surface. It
has become more matte. The dust and dirt that couldn't be removed
from the photograph before it was separated from the glass is still
present on or in the emulsion. We have tried several solvents, but
the liquid wipes not only away the dirt, but also the colour of the
photograph.

Is there anyway that this sensitive picture can be cleaned?

Rebecca Heremans
Student 3th Bachelor Conservation and Restauration of Visual Media
Blindestraat 9
2000 Antwerpen, Belgium


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                  Conservation DistList Instance 23:39
                   Distributed: Friday, April 9, 2010
                       Message Id: cdl-23-39-029
                                  ***