44th Annual Meeting, Photographic Materials, Tuesday, May 17, Separation Anxiety: Kiss Your Acetate Goodbye! – by Nicole Christie and Cindy Colford.

In a presentation related to the Disaster theme of the conference, speakers Colford and Christie spoke of the recovery of flood damaged photographic collections of the Peterboro Municipal Archives, in Ontario in 2004. The area wide disaster created such demands on affected infrastructure that the response began two weeks after the peak flood, which led to a decision to freeze all the of works, including glass plates and film negatives as other methods of drying had not been possible. The PMA participated in a CCI risk assessment which reported back with recommendations to keep all film stabilized in freezers for continued cold storage, and to identify cellulose acetate negatives as a specific priority for treatment due to their autocatalytic behavior, leading to eventual change and loss of values.
The authors, looking to Pavelka & Naipavel-Heidushke’s paper on successful treatment and separation of gelatin image layer from acetate support, called out Pavelka’s suggestion that insurance companies might provide financial assistance for treatment in their coverage. Following the protocol suggested in the article, the authors proceeded and achieved inconsistent results. They noted the process per negative could take up to ninety minutes, resulting in only four negatives treated over two days, They cited concerns of prolonged exposure of the negative to solvents, yet found it hard to keep solvent from evaporating, which could induce curl and tensions while drying. A new question developed, what was the difference between the article’s case studies vs. theirs? An obvious variable was the fact that these items had been frozen. Whether or not this actually factored into the negatives’ behavior. Consulting further with Greg Hill (currently of the Canadian Conservation Institute) & Gayle McIntyre (Sir Sandford Fleming College), the protocol was revised to include the following steps, which helped increase the reliability of the method across different negatives:

Silver gelatin pellicle being separated from acetate support
Silver gelatin pellicle being separated from acetate support

1. Remove material by cutting away some of the lip/edge of the negative to allow ingress of solvent
2. Prewet the negative using sequential solvents
3. Use visual and tactile clues to determine the moment of separation (need slide 3.1, 3.2.) not a fixed amount of time
4. If the gelatin is still disrupted, reshape while it is still wetted using gentle prodding (with  brushes on silicon release Mylar*) to lay flat before drying completely.  The unsupported pellicle, thin as tissue, can be left to release final residues of solvent in a non-stick drying pack in fume hood to offgas.
(More images of these steps available in the downloadable Kiss Your Acetate Goodbye images of layer separation, pdf file kindly provided by the speakers.)
The images, now supported on Mylar sheets, were digitized, and the storage solution after treatment includes use of polypropylene sleeves in a clamshell binder. In an added benefit, the items are no longer taking up space in cold storage. The authors report that after eight years, the images appear unchanged in these conditions. While having a positive outcome, the speakers note that is still a lengthy process involving time and material costs, requiring trained professionals. This technique may not be a catchall for all collections, but for prioritized ones, it can be effective management tool for severely decaying negatives.
*Additional note: Silicon tip tools may also be useful here. See related content from 2016 BPG Tips Session on Silicon Shapers, as found in art supply stores today among the brush selections for working thick paints, in the BPG wiki.

42nd Annual Meeting – Photographic Materials, May 30, "Preservation of Deborah Luster's One Big Self" by Theresa Andrews

Luster is a Louisiana based artist who began her own career in photography in 1988 after the death of her mother. Both her mother and grandmother were photographers. One Big Self is an artwork comprising 287 4″ x 5″ silver gelatin developed out photographs on aluminum plates, stored in a steel cabinet with three drawers, and a lamp on top of the cabinet to facilitate viewing. The photographs are portraits of Louisiana prison inmates taken between 1998 and 2002. On the back of each metal plate is a personal description of the person in each photograph. The artwork is intended to be interactive, allowing the viewer to handle the photographs and read the inscriptions, seeing the subjects as real people. The metal plates are covered in paint, followed by the gelatin emulsion layer used to print the photographic image which is selenium toned. Creating these plates is very labor intensive, and Luster only manages to produce three to four plates per day. She inscribes the personal information about the inmates on the plates with a dremel tool.
The San Francisco Museum of Modern Art (SFMoMA) was faced with the challenging task of displaying One Big Self in the way the artist intended – as an interactive work – after it was acquired in 2003. The security and physical preservation of the photographs were the two biggest threats to the work. The piece ended up being displayed alone in a room with one museum guard on duty at all times, which seemed appropriate in the context of the artwork’s subject matter. It was decided that only 200 plates would be displayed at any time, and twenty portraits were randomly selected to never be displayed. The plates that have been on display have indeed seen changes. Some plates have been caught in the drawers and become bent, edges of the emulsion on some plates have been abraded, and some of the plates have yellowed. Although the artist is dismayed at learning about the yellowing, the cost and time of replacing each plate as it becomes too worn to be viewed makes reprinting each portrait an inefficient solution. Out of the total 287 plates, excepting the 20 that will never be displayed, only 200 are on display at any given time, so 67 plates can still be swapped with any plates that become too damaged for exhibition.
Summary by Greta Glaser, Owner of Photographs Conservation of DC

42nd Annual Meeting – Photographic Materials, May 30, "Fototeca Pedro Guerra: Conservation of the Photographic Archives" by Cinthya Cruz

The archives of Pedro Guerra are part of the Universidad Autónoma de Yucatán in Mérida, where the climate is hot and humid. Photographic prints and negatives in this collection include many photographic processes and materials, from albumen and silver gelatin to glass plates and nitrate negatives. The goals of the photo archives are to stabilize the existing materials, catalog and organize the objects, and monitor and maintain a safe environment. Condition issues affecting the collection include broken and scratched glass, finger prints, sticky emulsion, and fungus. Nitrate negatives are immediately placed in frozen storage in Marvelseal bags after they are treated and scanned. Object codes and registration numbers specific to the archive are written on the exteriors of the bags so negatives can be located when necessary. Enclosures for other photographic materials, such as sink mats for broken plates and acid-free paper envelopes for photographic prints, also contain object codes and registration numbers. The object codes refer to the subject matter contained in the photographic image and the type of object.
Summary by Greta Glaser, Owner of Photographs Conservation of DC