Ms. Fischer’s talk focused on megalethoscope slides, an uncommon 19th century photographic process. When a group of these slides were brought to the Northeast Document Conservation Center (NEDCC) their conservation presented some challenges. Particularly, the lack of primary sources on the construction of the slides themselves. Further, the slides bridge conservation specialties, since they are comprised of albumen photographs on a wooden support. Ms. Fischer and her colleagues at NEDCC came up with some innovative treatment approaches to conserve these unique objects. Fischer underscored the collaborative nature of this project, which included FAIC, the George Eastman Museum, and numerous departments at NEDCC.
Megalethoscope slides are albumen prints mounted to a concave wooden support. Slides are placed into a viewer, which creates the illusion of depth and enlarges the image. The image can be lit from front (reflected) or back (transmitted) to create visual effects.
The first challenge of this treatment project was the lack of contemporary or historic information about the process. Fischer indicated one publication from 1999 that talked about the conservation of Megalethoscope slides and gave some helpful diagrams: Topics in Photographic Preservation 1999, Volume 8, Article 5 (pp. 23-30) “Megalethoscope Plates A Case Study: Conservation Treatment of Megalethoscope plates from the Collection of the ‘Museum for Art and History’ Brussels, Belgium” by Sylke Heylen and Herman Maes with supervision of Roger Kockaerts http://resources.conservation-us.org/pmgtopics/1999-volume-eight/08_05_Heylen.html
In order to learn more, Fischer worked with Mark Osterman, Photographic Process Historian at the George Eastman Museum (GEM). Todd Gustafson from the GEM also contributed because they have some megalethoscope viewers in the collection. Period megalethoscope slides at the GEM to were examined to extrapolate the process. Damaged slides proved to be the most useful for this, as they allowed for examination of the layers. The process Fischer described was complex. To summarize: They created albumen prints from digital negatives. The photographs were pierced from the front. The reverse of the print was painted with watercolor. A convex frame was made from bent pine. The photograph was attached to the frame using hide glue and then the edges were taped with black paper tape. Tissue paper was then added to the reverse. A dust cover was then added to the back of the slide.
Fischer showed a video of what it is like to view their re-created megalethoscope slide through the viewer. The scene began with reflected light, showing a landscape that was deceptively 3-dimensional. The light then transitioned to transmitted (behind the photograph), and the sun appeared to set in the scene and previously un-seen holes in the photograph created dramatic lights in a night scene. The effect is quite unique and certainly impressive.
The conservation treatment was designed to address the major condition issues: significant dirt, fly specks, tears and brittle dust covers with bug damage. The tear mending required some inventiveness because of the concave nature of the object and the layered structure. Fischer and other NEDCC conservators adapted a technique from Japanese panels in order to repair the tears. In this technique blotting paper supports are held in place with string to support the tear as it dries. After drying the string is cut. The dust covers were original, but highly damaged. A remoistenable lining was used to stabilize the dust cover, while minimizing moisture.
Finally, the inpainting of these photographs also presented challenges, since it had to be effective in both reflected and transmitted light. They mixed these two lighting techniques during inpainting.
In the question session following the talk, Fischer indicated that they used Gamblin Conservation Colors for inpainting because they were more translucent than watercolor. The book conservation department at NEDCC created custom phase boxes to house and protect the slides.