Photographs Under the Loupe of Science
By Dusan C. Stulik and Art Kaplan
experimental 1854 photo

For over a decade, the Getty Conservation Institute has conducted extensive research on the conservation of photographs. This work has included the development of new, scientifically based methodologies for the identification of over 150 historical photographic processes and their variants. In recent years, this work has been enhanced by GCI scientists using the latest advances in scientific and analytical technology to create a portable analytical laboratory. This traveling laboratory can be packed into a container the size of a suitcase and transported to museums, galleries, and existing conservation laboratories.

The portable laboratory has modified the usual modus operandi of the analysis and scientific investigation of photographs. Instead of bringing photographs to the scientific laboratory, sophisticated analysis can be performed using nondestructive, and sometimes even noncontact, instruments directly in collection storage areas. Taking the analytical equipment to the photographs (instead of the other way around) eliminates the need for insurance, the potential for damage to the material during transportation, and the removal of the material from its controlled environmental conditions.

Work with the portable laboratory has facilitated a number of important collaborative research projects that are beneficial to both the GCI research project and to the collaborating collections, which gain access to scientific data that allow for the reliable identification of photographs—and, in many instances, lead to corrections, changes, or enhancements of registrar information for a collection.


One of the most extensive collaborative projects to utilize the GCI portable laboratory was initiated in 2006 between the GCI and the National Media Museum (NMeM) in Bradford, England. The NMeM's collection of historical photographs is one of the most wide ranging in the world; it includes more than 250,000 images—among them more than 6,500 photographs by William Henry Fox Talbot and several photographic images made by the inventor of photography, Joseph Nicéphore Niépce.

Curators of the NMeM photographs collection identified a number of unusual photographic images that either were not well described in their registrar records or were missing photographic process information. Working closely with curators who conducted historical and art-historical research on the same images, the GCI team solved a number of photograph identification puzzles that had bothered museum curators for a long time. The examples described below illustrate different aspects and challenges of the scientific and historical study of photographs from the NMeM collection.

salt photographic print

Photographer William Willis's original platinotype formula was patented in 1873, and his new, improved, and "silverless" platinotype process was patented in 1878. The NMeM collection has a mounted and framed display of Willis's different platinotype photographs, starting with his first attempt to coat a paper substrate with platinum chloride. Later successful examples of different silver- and gold-toned platinotype prints, using both the 1873 and 1878 platinotype processes, are also displayed. It is not known exactly who put the display together and when. After the analysis was conducted, it became evident that some of the descriptions on the display mount did not accurately reflect the chemical composition of the materials. It is important for the future care and interpretation of these photographs that we can now prepare a corrected version of the notes related to Willis's platinotype experiments.

Frederick Evans's photograph Height and Light, Bourges, taken in 1900, was presented in 1937 to the Royal Photographic Society Collection of Photographs, currently housed within the NMeM. While the photograph was described on the back as a platinum print, its brownish tonality raised questions among NMeM curators. The XRF analysis, together with the microscopic investigation of the image microstructure, showed that the print is actually a photogravure, printed using iron pigment–based printing ink. This finding indicates that the mere visual identification of platinum prints is not always accurate, and that much cheaper photogravures may pass as expensive platinum prints. (We do not know if Evans himself originally advertised this print as platinum!)

XRF analysis

Infrared (ATR-FTIR) analysis of a William Henry Fox Talbot experimental photograph from 1854 confirmed the inscription clearly visible on the photograph: "Collodion process on paper." If the date on the inscription is genuine, this experimental print might be the first successful test of a collodion-based light-sensitive layer coated on a paper substrate. The history of photography does not describe the use of collodion on paper prior to the second half of the 1860s. What made this Talbot experimental photograph even more interesting was the XRF analysis of the print. The analysis showed a relatively high concentration of barium and strontium, which usually indicates the presence of a baryta layer—a smooth, inert, white coating layer of barium sulfate in gelatin applied to the photographic base in some processes. To find the application of a baryta layer on an 1854 Talbot photograph was a surprising result. If future historical research proves that the experimental print was indeed made by Talbot in 1854, we will need to change not only the date of the first use of collodion on paper but also the date of the first known application of a baryta layer in photography. If this is proven, Talbot will gain two more important photographic inventions, adding to his already long list of photography firsts.

Some of the findings from the GCI–NMeM collaboration have been less exciting, even disappointing. One of the photographs in the NMeM collection was described on its mount as "First Photographic Print Made by Vanadium" by Captain William de Wiveleslie Abney, an important British photochemist of the second half of the nineteenth century. The project team looked forward to the opportunity to record the first analytical signature of the vanadium process. Our historical investigation of the vanadium process in nineteenth-century photographic literature suggested that analysis should reveal a gelatin coating and detect vanadium as the image-forming element.

However, the XRF analysis of the "vanadium photograph" did not reveal any trace of the expected vanadium. Instead, a high concentration of silver was found. Moreover, the infrared analysis of the photograph did not yield evidence of a gelatin coating. In fact, it would appear that the photograph is just a silver-based salt print. We know that a vanadium photograph is out there somewhere—but we will need more time to find one to use as a sample.

The GCI–NMeM collaboration will provide a wealth of information, not only to both institutions but also to the photographic research community and the public visiting the NMeM. The new information obtained on a number of photographs will add another level of information to the NMeM photography collection. We hope that other museum collections will follow the lead of the NMeM and attach results of analytical investigation to their registrar information, for the benefit of photograph conservators and art historians studying material aspects of photography and photographic technology. Many elements of the GCI–NMeM collaborative project have been published and presented at conferences of the photograph conservation community, and more publications and research tools will be available in the future to conservators and conservation scientists researching photographs.

Dusan C. Stulik is a GCI senior scientist. Art Kaplan is a GCI research lab associate.