Treatment of water-damaged paintings

In reviewing emergency response recommendations for water-damaged
oil paintings on canvas, it became apparent there are two schools of
thought on the subject. Some authors suggest drying unframed
paintings with low impasto face down, with weighted blotters on the
reverse of the canvas (the way one would normally proceed to flatten
distortions), while most others suggest that air drying unframed
paintings, face up, is the way to go. I can understand this approach
for a painting which has severe tenting or flaking. However, it
would also seem that air-drying paintings face up would not only
retard the evaporation of moisture (assuming it would desorb most
readily from the more hygroscopic material--the canvas), but also
induce sagging of the canvas and deepen stretcher marks. One can
also assume that most paintings dried face up in this manner would
eventually have to be re-dampened and re-dried face down in order to
remove canvas distortions.

I would be interested in hearing comments from conservators who have
first-hand experience with this. What would you suggest?

Michael O'Malley
Paintings conservator
Centre de conservation du Quebec

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                  Conservation DistList Instance 11:27
               Distributed: Wednesday, September 17, 1997
                       Message Id: cdl-11-27-007
                                  ***