SOLVENT CLEANING OF ANTIQUE CHROMOGENIC PRINTS: AN ANALYTICAL COMPARATIVE STUDY

Abstract

Chromogenic prints were the classic form of color photography in the latter half of the 20th century. Overall, photographs are considered composite objects with complex structures. However, color photographs are much more complex in structure than black and white; and therefore present special preservation challenges. Since photographs are in high demand due to their numerous applications, they often suffer from damage as a result of improper and frequent handling. Particulates, which may be greasy, grimy, abrasive, and chemically or biologically active, settle on shelves and on collection materials causing both physical and chemical damage. Accordingly, photographs may benefit greatly from surface cleaning treatments. Treatments chosen for this experiment were based on the following solvents: acetone, toluene, ethyl alcohol and isopropyl alcohol. Changes promoted in the binder and image silver, as a result of these treatments, were measured in order to evaluate the benefits and potential problems of each treatment and estimate if they can be used without unacceptable change in the original image now and in the future. The tests are based on the consideration of the following criteria: changes in the surface characteristics through digital imaging, atomic force microscopy (AFM); changes in the density of image silver through densitometric measurements; changes in the chemical structure of the gelatin binder through attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), changes in color and gloss through spectrocolorimetric measurements; and disturbance of the binder (i.e. ninhydrin test). Data obtained from naturally and artificially aged samples were compared with those of the control