More than Meets the Eye: Restoring the Danz Collection

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Guest post by Tracy Power Objects Conservation and Lesley Bone

Funding for this project was generously provided by the Francis I. Proctor Foundation for Research in Ophthalmology at UCSF.

Since 1963, the UCSF Archives & Special Collections holdings have included the historic Danz collection of ocular pathology specimens. The set, one of 13 believed to have been made, was originally intended as a teaching tool for use in medical schools. These blown orbs, some still retaining a long delicate stem, were made in Germany, in the 1880’s, by master glassblower, Amandus Muller. Each glass eyeball depicts, in minute detail, the various diseases and defects that can afflict the eye and is a unique masterpiece of the art of glass making. 

In June 2018 the collection was examined by Tracy Power and Lesley Bone to determine the nature and scope of condition problems that these objects.  Past treatments and current breakages were evaluated, the deterioration of the glass was examined, and current storage conditions were assessed.

While the majority of the glass eyeballs were in stable condition, there were ironically a couple that were themselves suffering from glass disease. This presents with a sticky surface; as a component of the glass leaches out of the surface due to an instability in the glass mix. These surfaces readily attract dust.

Of the previously repaired items, some were in stable condition, but most were in poor condition due to deterioration of the repair materials used and inferior skills of the person or people doing the repairs. One particularly peculiar repair was filled with bright red dental wax.

 The eyeballs were stored in their original compartmented box, with light damaged (faded), velvet-covered cavities for each specimen, and a hinged lid with a glass cover.  The box was still serviceable, but the cavities for the eyeballs had wads of old cotton wool, which was not suitable for the collection since the blown balls retained the thin tubular glass extensions that had been snapped from the rod when the ball was blown. These tended to snag on the cotton.

A treatment plan was agreed upon which would include upgrading the storage container, cleaning all of the glass eyeballs, and repairing the broken glass orbs.

Improved Housing

The eyeballs were removed sequentially for cleaning, and at that time the cavities in the display box were cleaned and new, improved supports were made.  The old cotton wool was replaced with new storage materials that will not be as likely to snag the glass tips.  Small pillows were made of polyester batting in Holytex fabric.  The glass pane in the box was cleaned with detergent and water.  Several discolored areas of paper on the box were toned with conservation stable watercolors and some lifting edges of paper were glued down.

Danz collection of ocular pathology specimens
Old cotton wool was removed and replaced by individually made pillows of archival materials.

Cleaning of the glass eyeballs

Each glass eyeball was carefully cleaned.  A detergent designed specifically for cleaning glass was used for this process.  Handling the eyeballs safely was a major concern and we ended up using foam tubes to make little doughnuts for the glass balls to sit in.  The foam was held in place with toothpicks, so their creation and adjustment was relatively quick. During the cleaning we identified some additional cracks in the glass eyeballs that hadn’t been obvious until they were wet up.  This step was very satisfying as the eyeballs went from dull and cloudy to glistening after cleaning.

Cleaning of the glass eyeballs
Cleaning the glass and the compartments in the box.

Repairing of Glass Eyeballs

Before the eyeballs could be repaired, those with unsightly or failing old repairs had to be undone.  The method varied depending on the types of repair materials previously used.  Several of the repairs had been done with red wax.  The wax remained soft and sticky making it messy and it did not closely resemble glass.  The wax material was removed by gently warming it.  Some of the other old adhesives had failed after becoming brittle.  The brittle material could be brushed from the surfaces, with special care taken to not scratch the glass.  Other old repair materials were removed with solvents.

Repairing the individual eyeballs was the most challenging part of the process, as they are thin and delicate.  Added to that, the high-grade epoxy that was designed for glass conservation can take several days to fully set.  While this can be advantageous, as it allows adjustment of pieces, it also means the fine shards have to be held in place for long periods of time while the resin sets. An advantage of this epoxy is that it is very thin and can be fed by capillary action into cracks.  That property was useful for many of the eyeballs. Also this adhesive has the added advantage of being far superior to commercially available epoxy resins in terms of long-term stability and greater light-stability, therefore it does not yellow like commercially available epoxies. 

Once the eyeballs were repaired, a few had areas where the fragments of the glass were still missing. Glass eyeballs that were incomplete were filled with tinted thermoplastic resin mixtures and details such as veins, were inpainted (inpainting is the process of restoring lost or deteriorated surface decoration or details on an artwork) with commercially ground pigments in acrylic resin.

The glass eyeballs were incredible to work on.   They were beautifully made, if often difficult to look at.  Only one of the eyeballs examined was failing due to unstable glass, or a poor match between the cream under layer and the colored surface glass.  The glass blower had incredible mastery in working with glass in addition to skill in depicting the defects and conditions.  We hope that after this conservation project the glass eyeballs continue to illustrate medical conditions and inspire awe for years to come.

DASHM adopts Jacob Bigelow’s American Medical Botany

We’re pleased to announce that two of our books have been adopted!

The UCSF Department of Anthropology, History, & Social Medicine has chosen to conserve American Medical Botany. Read more about the book from the perspective of Sarah Robertson, a PhD student in the department.

Additionally, the always supportive Bay Area History of Medicine Society has graciously taken De humani corporis fabrica libri septem under its wing.

Robert L. Day Collection: Anatomy of an Archival Project – Part 3

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.

William Martin Searby (1835-1909), crayon enlargement. Portrait before treatment.

William Martin Searby (1835-1909), crayon enlargement. Portrait before treatment.

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.

Searby portrait before and during treatment.

Searby portrait during treatment.

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.

William Martin Searby (1835-1909),crayon enlargement.Portrait before treatment.

Searby portrait after treatment.

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
Photograph Conservator
Gawain Weaver Art Conservation
http://gawainweaver.com/