Investigation on the Organic Acid Content inside the Storage of a Woodblock Print Collection and Evaluation on the FFU System as a Mitigation Strategy

Abstract This paper describes an investigation on the storage environment of an Edo period woodblock print collection in terms of volatile organic acid content, using active air sampling and precision gas detector tubes that can measure organic acid emissions in the low microgram range, and evaluates an organic acid mitigation method based on the fan filter unit (FFU) system. Ion-exchange chromatography method was also employed for estimation of acetic and formic acid ratio. Findings revealed an organic acid-concentrated microclimate inside the storage box, nevertheless, the off-gassing rates of the woodblock prints were low, with the exception of a print positioned in the middle of the stack. The acetic acid/formic acid ratio was similar between the storage room environment and inside the storage box, but comparatively higher levels of formic acid were identified in the mulberry paper folder housing the prints. Finally, the FFU system was able to reduce organic acid concentrations inside the storage box for a 5-month observation period, but it did not eliminate the tendency of the storage materials to create organic acid-concentrated microclimates.