Study on the Reduction of Acetic Acid from Cabinets for Microfilms (II) -Estimation of Emission Sources of Acetic Acid Gases in a Preparation Room and Removal of Acetic Acid from Paper Photographic Enclosures

The goal of the present study is to improve indoor air quality in a film storage and surrounding environment in the National Research Institute for Cultural Properties, Tokyo. This report addresses the estimation of emission sources of acetic acid in the film storage and adjacent preparation room,and presents an experiment to remove acetic acid from paper photographic enclosures kept as archives. To estimate emission sources of acetic acid, concentration and ventilation amount of acetic acid were measured in the film storage and the preparation room. It was found that air containing acetic acid flowed to the preparation room from the film storage and that a large volume of acetic acid had been emitted from cabinet 3 in the preparation room. There were aged films in the film storage and paper photographic enclosures which had absorbed acetic acid in this cabinet. Consequently, it was considered that acetic acid concentration of the preparation room was high. Removing the paper photographic enclosures from the preparation room would be the best way to reduce acetic acid. However, they should be kept as archives since they contain much information about the films. Therefore, seasoning of the enclosures wasattempted. As a result, their acetic acid emission rate was decreased in the first 35 days of seasoning. Furthermore, A-D strips were used to check the removal of acetic acid from the enclosures. The color of the A-D strips was changed in accordance with acetic acid concentration of the samples. This result was consistent with the trend of emission rate decay shown by emission test. Thus A-D strips were beneficial in checking easily the removal of acetic acid from the paper photographic enclosures.