During exhibition planning at the Harry Ransom Center, conservators assess all objects the curators have chosen for display. Conservators evaluate the condition of selected items to determine if any materials are sensitive, if items require specific conditions to be exhibited safely (e.g., support cradles for books or lower lighting for photographs), and which photographs—as in the case of Elliott Erwitt: Home Around the World—may need conservation treatment.
Two photographs featured in the exhibition and drawn from the Alfred A. Knopf, Inc. Records, had old pieces of transparent tape directly over the image. Conservators refer to this kind of tape as “pressure sensitive tape,” because it needs only light pressure to stick easily to most surfaces. As the rubber-based adhesive contained in the tape ages, it becomes quite rigid and discolored. In the case of the Erwitt photographs, since the tape was placed directly on the photographs, the discoloration was affecting the aesthetic presentation of the image. Moreover, it was quite possible that the stain could become permanent if the adhesive residues remained in contact with the photographic emulsion. Conservation treatments, hence, aimed to remove the tape and its adhesive residues.
Our first step was to properly identify the photographic technique of each item, so that we could choose appropriate cleaning techniques: In this case both photographs are gelatin silver prints on fiber base paper. An initial surface cleaning removed any grime to prevent deterioration of the print and complication of the next treatment steps. These Erwitt photographs were cleaned on the back using sulfur-free vinyl erasers, and the emulsion was cleaned on the front using very small cotton swabs, moistened in appropriate solvents.
To remove the tape, the plastic carrier was removed by using controlled application of a narrow stream of hot air, locally applied to soften the adhesive, allowing removal of the carrier layer with small tweezers. This procedure was careful and precise, in order to avoid alterations in the shine or texture of the photographic emulsion. Discolored adhesive residues were then softened using appropriate solvents, and at the same time picked up using cotton swabs.
Finally, areas where the emulsion was cracked or lifting were consolidated under the microscope, using diluted photographic grade gelatin and lightly applied weight.
In this case, the happy results are images free of stains, ready to be appreciated for their subject, tonal values, and composition.