45th Annual Meeting – Photographic Material Session, May 31st, “Providing Access to “Overprotected” Color Slides” by Diana L. Diaz-Cañas

Photograph conservator Diana Diaz introduced her presentation as a study case which deals with “overwhelming protection” of photographic materials.

The project started in 2006 when the Harry Ransom Center acquired the photographer Arnold Newman’s archives, including various photographic and other materials, such as photographic albums, sketch books, documentation of many projects… and color transparencies.

More precisely, a corpus of 35 mm Kodak Kodachrome color slides in plastic mounts was found. The slides were wrapped together with sealing tapes, forming in 16 sets. The tapes displayed, on the edge of each pack, handwritten inscriptions indicating the dates and subjects of the photographs. The dates inscribed on the tape enabled to date each project, the whole collection ranging from 1954 to 1972. Diana Diaz showed several examples of the images, like one taken for a project shot in Spain in 1970 for Holiday Magazine.

These slides series are of interest as they inform on the photographer’s working methods. For instance, they showed different cropping, compositions, and exposures experimented within each series. One can see how Newman would play with lights and colors and produce variations of the same images, among which he would then make his final selection for the publication. Diaz then listed all the assignments projects covered in the slides, shot in various places (Spain, Canada, California…) for different magazines, such as Harper’s Bazaar or Life.

However, when the slides were found, the images were still inaccessible since after the removal of the tape applied on one edge displaying the inscriptions, another white tape underneath maintained the stacks of slides together. Three types of tape were identified among the 16 sets:

  1. a masking tape;
  2. a discolored white tape;
  3. a white tape still tacky.

The conservation treatment needed then was difficult to engage because the tapes were in contact, not only with the slides mounts, but also with the films themselves – on both the image and support sides.

Therefore, to remove the tape carrier, Diaz logically proceeded by types of tape.

  • The white tape still tacky was removed mechanically with a spatula, without any adhesive residue left at the end of the treatment.
  • The masking tape was strongly adhered and did require a heated spatula combined with the use of solvents.
  • The discolored white tape was removed with the help of water vapor.

After all the carriers were removed, Diaz evaluated the materials and condition of the residual adhesives in order to determine which solvent to use. She referred to Smith et. al.’s paper1, which not only presents the history of pressure sensitive tape and their ageing properties, but also appropriate solvents and suitable methods of application for their removal. Thus, Diaz used naphtha (a mix of hydrocarbons) to successfully remove the rubber-based adhesive, and ethanol for the oily adhesives. The solvents were applied gently with a cotton swab in a circulation motion and in one direction to minimize the scratches and increase the efficiency.

The photographic documentation under Ultra-Violet illumination allowed to assess the removal of all the adhesives. Finally, the slides were individually rehoused in conservation materials.

Although this treatment was successful, several questions are being raised: Are there remaining solvents residues in the photographic materials at the end of the treatment? Has the surface been scratched? Indeed, the topic of the effect of solvents on color transparencies, in particular regarding the innocuousness for the photographic materials, would require further research to help photograph conservator to choose a suitable treatment.


1 Bibliographic reference: Merrily A. Smith, Norvell M. M. Jones, Susan L. Page, & Marian Peck Dirda. “Pressure-Sensitive Tape and Techniques for its Removal From Paper”
JAIC 1984, Volume 23, Number 2, Article 3 (pp. 101 to 113