Topics in Photographic Preservation 1997, Volume 7, Article 5 (pp. 36-37)
Severely flaking gelatin dry plates are a problem conservators have yet to solve. Small localized flakes have been successfully readhered with gelatin, methyl cellulose, or synthetic resins; but, as far as I know, these procedures have not been successfully applied to large areas of emulsion flaking. One possible solution, the use of moisture in combination with a resin, had been suggested in the literature, but it had not been tried. Last year, I was given an expendable, severely flaking dry plate, and decided to experiment with the moisture/resin combination.
This 8″×10″ gelatin plate appeared to have been water damaged. There was fading of the image around the edges, severe flaking over one-third to one-half of the plate, and deposits of white crystals on the emulsion. Also, the white crystals were between the glass and emulsion, forming a gritty surface on the glass in these areas. The flaking emulsion was badly cupped, and I noticed that the flaking generally occurred in the low density areas of the negative.
From my experience with glass plates, I knew that applying an aqueous consolidant over such an extensive area would cause emulsion expansion problems. I also knew that a resin such as acryloid B-72 might hold the flakes in place, but would do nothing to relax them so they could lie flat. To circumvent these problems I attempted to set the flakes down with acryloid B-72 while humidifying the plate with moisture.
The procedure was as follows.
During subsequent treatment of several additional plates with less extreme flaking, I determined that the long period of drying in a humid environment was not necessary. In fact, I suspect this may have promoted the formation of the white crystals. Instead of using a chamber, the plates were locally humidified as needed, using the hose attached to the ultrasonic humidifier. Humidification in this way was repeated until the acryloid B-72 had dried enough to hold the flakes in place.
In the course of these treatments, additional changes were made to the procedure. Also, several potential modifications came to mind.
As stated in the title, this procedure is tentative. It has not been extensively used or time-tested. Hopefully, it is the first step in the development of a successful treatment technique for severely flaking gelatin dry plates.