AIC's 47th Annual Meeting

Recent developments in the use of polysaccharide gels and washing solutions have expanded conservators’ choices for treating paper-based materials beyond traditional aqueous immersion washing. A project to treat European prints depicting African scenes, in the collections of the Library of Congress, provided an opportunity to compare several cleaning protocols: washing by gellan gum, washing in conductivity-based solutions and chelators identified by Richard Wolbers, and washing in calcium-hydroxide-adjusted alkaline water. The goal of the treatment was to reduce staining, overall discoloration, and acidity in nine engravings on eighteenth-century laid paper supports. The prints were documented before, during and after treatment with digital photography, UV-induced visible fluorescence imaging, colorimetry (CIELAB), and reflectance spectroscopy (Fiber Optic Reflectance Spectroscopy or FORS). Conservators and scientists utilized FORS, a sensitive and non-destructive optical sensing technique, to measure the color of the paper before and after treatment. The results of FORS measurements were correlated with brightness-meter and spectroscopy readings, to obtain ∆E data for comparison with the traditional measurements. This presentation will compare and contrast the results of the three treatment protocols, outline practical advantages and disadvantages of each, and discuss the application, versatility and usefulness of FORS to evaluate the treatment outcomes.