The Treatment of Microbubble Disease of 20th Century Cellulose Acetate Microfilm: Application of Ethyecellulose and Microrepair Method 

Abstract

Microbubble disease observed in cellulose acetate microfilm was accompanied by the production of vinegar syndrome, which has a negative influence on the integrity of image. In the present study, cellulose acetate microfilm with microbubble disease from the Republic of China (AD 1912-1949) collected in the Second Historical Archives of China was chosen as a prototype to investigate its treatment methods. A combination of optical microscopy and a stainless-steel needle was used to remove plasticizer exudation within microbubbles. The plasticizer was effectively removed by infiltrating butan-1-ol into the microbubble from a small hole made by the stainless-steel needle. The SEM and laser confocal microscopy were used to study the morphology and roughness of the internal surface of microbubble. It was found that the blurry image could be attributed to the light scattering from the rough surface. Based on the advantages of ethyl cellulose in conservation science, the optimal concentration of ethyl cellulose was selected and used to fill the interior of the microbubble to obtain a clearer image. To determine the protective potential of this filling material, the chemical and mechanical properties of coated film after dry heat, hygrothermal and UV accelerated ageing were measured. Based on the above-mentioned results, it is encouraging that a new microrepair method and its corresponding method are offered in film treatment work.