X‐ray fluorescence portable systems for the rapid assessment of photographic techniques in notable art collections: the Alfred Stieglitz Collection

Abstract

AbstractIn the late nineteenth and early twentieth century photographers experimented, adapted and combined different techniques, using a wide array of chemicals leading to a vast range of commercial and self‐made photographs. Museum professionals, experts and collectors typically rely on visual and microscopic examination to identify photographic processes, however, visual identification alone can be misleading. The present study describes applications of portable and handheld X‐ray fluorescence(XRF) spectrometers to determine the metallic elements in photographic images, with special focus on one of the highest‐profile photographic collections in the world, that of Alfred Stieglitz. A protocol was developed for two types of XRF spectrometers, a portable micro‐focus system and a handheld macro‐set‐up, and validated with standard replicas of known photographic techniques. Qualitative XRF identification of the metallic salts allows unambiguous identification of the process used for each photograph. The portability of the systems makes the method applicable to the study of large collections in any location. In total, more than 60 photographs from the Alfred Stieglitz Collection were analyzed, leading to the revision of approximately 16% of the previous process identifications. These results are presented here for the first time. The correct identification of these photographs has significant impact on aspects of preventive conservation, exhibition and scholarly research, not only for the Art Institute of Chicago but also for other institutions and private collectors who own photographs from the Alfred Stieglitz Collection. Copyright © 2009 John Wiley & Sons, Ltd.