Recently, the conservation lab was besieged by a large collection of discs that had an odd surface coating of a white waxy residue. The discs were being processed as part of a Robert Frost collection located in Rauner Special Collections Library, and contained recordings of interviews and lectures of Mr. Frost at Dartmouth College.
With a first go around on the internet I came across detailed information on how many variations of disc manufacturing there are: vulcanite, shellac, Columbia, Edison, vinyl, and acetate, which is the least stable one. These have an interior base of aluminum or glass and sometime cardboard. These inner cores are coated with nitrocellulose lacquer plasticized with castor oil. It seemed that most of what we had were indeed acetate.
The white substance was something I had never seen and my previous knowledge of how to clean albums didn't seem applicable to these. At first some of my colleagues thought the substance was mold but on further investigation and inquiry I came across this great dialog between Anji Cornette, The Cutting Corporation, and Alan Lewis, National Archives and Records Administration, and based on what they said I determined that it must be palmitic acid. "The production of palmitic acid is caused by the hydrolysis of the castor oil from heat and humidity, which then oozes through the lacquer on a disc. The specks or small mounds on the groove look similar to powder residue but have a more crystallized appearance. Palmitic acid is stubborn to remove and requires extensive cleaning."
Realizing that this was more than a simple cleaning, I contacted The Cutting Corporation. They were great and very forthcoming in talking about the whole process of deterioration and the different service options.
Once we chose to send out the discs for cleaning, Aaron Coe, our contact there, worked with two Rauner staff members to decide if they would have a digital copy made in addition to cleaning (which we did). All transactions went smoothly and Aaron sent me a set of photos of the cleaning (thanks Aaron!). The discs have been returned and we are now able to listen to the voice of Robert Frost.
- Preserving Sound Recordings by Stephanie A. Hall
- The Care and Handling of Recorded Sound Materials by Gilles St-Laurent
Written by Deborah Howe.