Conservation treatment of a portrait of William M. Searby
William Martin Searby (1835-1909) was an important figure in the founding of the California College of Pharmacy (later UCSF School of Pharmacy). In addition to being the school’s first professor of Materia Medica, and later professor of pharmacy, he was also dean of the college for many of the school’s early years.
A portrait of Professor Searby in the UCSF archives, taken perhaps in the 1880s, was found in disrepair. The portrait was done in a format known as a crayon enlargement, which is a photographic image enlarged onto paper and enhanced by painting over in various media including airbrush, watercolor, or charcoal. Crayon enlargements were introduced in the late 1850s with the introduction of the solar enlarger—a means for enlarging negatives using the sun. They continued to be popular into the early 20th century and can be found on the walls of your local antique shop, often in large numbers. They can be oval shaped and mounted onto convex boards and placed in oval frames, or like the Searby portrait they can be lined with fabric and then mounted onto a wooden strainer. The Searby portrait had a silver-based photographic image as its base and was worked over primarily with charcoal. It was still housed in its original 5” Florentine gilded frame, but the portrait had suffered over time due to light exposure, variations in relative humidity, a poor-quality paper support, and the wooden strainer. These led to losses, yellowing of the image, embrittlement of the paper, and large tears.
The portrait was brought to the photograph conservators at Gawain Weaver Art Conservation in San Anselmo, CA. The first step was to unframe the portrait and cut it away from the wooden strainer and then remove its fabric lining. The loose areas of the lining fabric were cut away with a surgical scalpel. However, the lining fabric was strongly adhered to the fragile print along the edges with a very stubborn adhesive. An enzyme poultice was used to weaken the starch component of the adhesive, but it was still very difficult to remove and had to be slowly mechanically separated after softening with enzymes. The print was then free from its support but the paper was still very brittle, yellowed, and in multiple pieces. The next step was to wash the paper to remove degradation products and restore some flexibility to the print and to light bleach the print to remove the overall yellowing and discoloration.
Light bleaching uses the free radicals generated by light interacting with water molecules to gently remove staining and discoloration in a print while it is being washed. Light bleaching was developed in Marin County by pioneering paper conservator Keiko Keyes in the early 1980s and since that time has been widely adopted by both paper and photograph conservators.
The pieces of the print were placed on a support and washed and light bleached until the discoloration was sufficiently removed and some flexibility had been restored. The fragile print needed mending and physical support, so these were accomplished together by lining the print with a thin and strong sheet of Japanese paper attached with wheat starch paste, the most stable and commonly used adhesive in the conservation of photographs and works on paper. The mended cracks and remaining losses were then filled and retouched to make them all but invisible to the viewer.
The original aesthetic of the portrait was perfectly flat. To achieve that flatness and to provide further physical support, the newly lined print was mounted overall to a sheet of 4-ply rag museum board. The glass was replaced with UV-filtering acrylic to eliminate the danger of breaking glass and provide protection from ultraviolet light. The old nails keeping the two parts of the frame together were dangerous and often very loose, so they were removed and the frame and print were assembled more securely to be put on display for the first time in many years outside the UCSF archives.
Gawain Weaver Art Conservation