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Wednesday, May 15 • 2:00pm - 2:30pm
(Electronic Media) Revisiting Chemical Reconditioning Of Cellulose Acetate Motion Picture Films For Improved Digital Reformatting

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A primary motion picture medium since the early 20th century, cellulose acetate film can be subject to brittleness and loss of dimensional stability due to polymer degradation and plasticizer loss. Although contemporary film scanners using advanced gate and roller technologies have significantly improved the quality of film preservation reformatting and increased the number of films that can undergo the process, many collections have physical deformations that preclude an acceptable scan or are too brittle to be scanned at all. These cultural artifacts are in danger of being lost. Formerly used to de-shrink films for reprinting, chemical reconditioning processes have been shrouded as trade secrets, but must entail the restoration of important physical and mechanical properties of films. As such, they are candidates to complement contemporary film scanning to further improve the number and quality of digitally reformatted motion pictures. In a proof-of-concept study using six film reels exhibiting mechanical and dimensional problems (all 16 mm, various stock types), we exposed test lengths to conditions commonly associated with reconditioning (water, acetone, camphor, and methyl phthalate vapors, -5 in. Hg, overnight). Measuring thickness and weight before and after treatment, and performing the destructive mechanical MIT Folding Endurance Test on treated samples versus untreated controls, we observed a statistically significant weight increase in all samples after treatment, suggesting solvent/plasticizer adsorption if not intercalation. We also observed a significant increase in both MIT Folding Endurance and thickness in the same two of six samples (both Kodak, ca. 1940), establishing that this chemical pretreatment can improve an objective material strength criterion. Given that we observed this difference overnight—when exposure times of weeks or months are documented for this process—we anticipate effects of chemical reconditioning to be readily observable in brittle or warped collections. Finally, we commenced a production team survey (21 questions, double blind) of our study collection (60 films: nine 8 mm, forty-six 16 mm, four 35 mm) for key scanning criteria before and after chemical reconditioning (and after subsequent reconditioning) to determine how this process might best compliment scanning for improved digital reformatting.

Speakers
avatar for John Baty

John Baty

Technology Manager, Preservation Technologies, L.P.
John Baty manages the research and development laboratory for the MediaPreserve and Bookkeeper Divisions of Preservation Technologies, L.P. (PTLP), which provides digital reformatting and deacidification products and services to libraries, archives, and businesses worldwide. He collaborates... Read More →
avatar for Diana Little

Diana Little

Supplier/Service Provider, Preservation Technologies
Diana Little has served as Head of Film Preservation at The MediaPreserve, a Division of Preservation Technologies, L.P., since 2010, managing the Film Lab and its team of six preservationists. She oversees all preparation of collection materials, archival scanning, post-production... Read More →

Co-Author
LV

La Verne Lopes

Senior QC Technician, Preservation Technologies, L.P.


Wednesday May 15, 2019 2:00pm - 2:30pm EDT
Passamaquoddy/Brothertown Rooms Sky Convention Center, Mohegan Sun
  Specialty Session, Electronic Media
  • Track Electronic Media
  • Ticketed Included in Main Registration
  • Authors in Publication Order Diana Little, La Verne Lopes, and John Baty
  • Abstract ID 18720
  • Tags cellulose acetate,motion picture,film,digital reformatting,brittleness,dimensional stability,physical deformation,chemical reconditioning,polymer degradation,vinegar syndrome,film scanning,de-shrinking,water,acetone,camphor,methyl phthalate,film thickness