A NOTE ON THE TREATMENT OF TWO GELATIN SILVER PHOTOGRAPHS BY HAROLD EDGERTON FROM THE PORTFOLIO “SEEING THE UNSEEN”
ABSTRACT—Technical information about Filmoplast-P is discussed and a procedure for the removal of the yellowed tape is described.
Placement Kick and Swirls and Eddie are two gelatin silver photographs by Harold Edgerton from the portfolio “Seeing the Unseen.” These photographs are privately owned as individual works separated from their portfolio. The portfolio was published in 1977 by Mr.Edgerton in an edition of 60, plus seven artist's proofs. Each portfolio box contains seven black and white gelatin silver prints on Kodak Polycontrast paper and five dye transfers, all measuring 11 by 14 inches. The photographs were taped at the top on the emulsion side with Filmoplast-P tape and then attached onto buffered mounts measuring 20 by 16 inches1. There are a total of 469 black and white photographs printed along with 335 dye transfers in existence which have been and probably still are mounted in this fashion.
Examination of the two photographs revealed a yellowed pressure-sensitive hinging material along the top edge. Removal of the tape was proposed due to its discoloration and possible deleterious effects on the gelatin emulsion surface.
2 TECHNICAL INFORMATION ON FILMOPLAST-P TAPE
Filmoplast-P is a thin, flexible, pressure-sensitive tape that has been sold throughout the world for twenty years as a product of archival quality.
Hans Neschen describes the product as follows2.
polyacrylate in a water dispersion neutral (pH balance 8.0) will not yellow can be removed with waterPAPER CARRIER:
bleached wood-free thin paper buffered with CaC03 manufactured expressly for this product silicone-treated
Pressure-sensitive adhesives are typically composed of a rubbery type elastomer, in this instance a polyacrylate, but may be combined with a liquid or solid resin tackifier component. A mixture of resins are sometimes used to provide a balance of properties that cannot be obtained with either resin alone. Many times fillers are added to change the rheological properties of the adhesive or to add color. Antioxidants are used to stabilize the adhesive against oxidation, heat, and light degradation.
Further analysis of the adhesive using infrared spechtrophotometry confirmed that the elastomer portion is a polyacrylate3. A strong indication of a plasticizer/tackifier portion was noted but this constituent and others could not be identified.
3 REMOVAL OF THE FILMOPLAST-P TAPE
Mock-ups were evaluated to determine the most successful conservation technique for the removal of the Filmoplast-P tape. The following procedure proved successful for removing the tape without damage to the emulsion layer of the photograph.
Distilled water was applied to the paper carrier using a wet but not saturated Series 7 Winsor and Newton #00 watercolor brush. The paper carrier was allowed to turn a milky-white color as it absorbed the water. If the carrier did not turn milky in color, a second application of the distilled water was applied. The paper carrier was then peeled back at the edge in one continuous strip using tweezers to keep the surface angle of the carrier very low at the point of separation from the emulsion. The adhesive layer remained. Again, distilled water was applied this time to the adhesive layer with a wet but not saturated brush. The adhesive layer was allowed to swell slightly and turn milky-white in color and was lifted with tweezers in one stretchy layer. The air-dried paper carrier and adhesive components were closely examined. The paper carrier appeared distinctly yellow in color while the adhesive layer was pale yellow. The emulsion of these photographs exhibited no damage from the tape. They will be checked annually and changes will be noted.
Despite the success of the treament to remove the tape, use of Filmoplast-P for applications to emulsion surfaces is not recommended, and its use for application to the paper support is questionable. The tape almost certainly underwent some kind of change during its six years of contact with the photographic emulsion, and while no damage to the photographs was observed, the possibility of long term damage cannot be ruled out. Information on all components of the tape is not available. Moreover, the formulation of the adhesive has recently been changed according to the manufacturer4. As with all commercial products, procedures worked out on old samples may not besuitable for use on newer samples.
1.. Edgerton, Harold, “Seeing the Unseen,” Colophon, p. 2 of portfolio included in the complete the set, 1977.
2.. Peter Kluge, Hans Neshen Gmbh Co. KG, P.O.B. 1340, D-3062 Buchberg, Federal Republic of Germany
3.. Hopwood, Walter, Report No. 4424, Conservation Analytical Laboratory Smithsonian Institution, Washington D.C. 20560.
4.. Conversation with Hans J. Denstroff Filmolux Inc., Buffalo, N.Y. (1987).