Remote monitoring of condition of archive celluloid cinematographic film - has acid-sensitive indicator located in opening in wall of can, behind lens and coupled in fluid contact with inside of can by passage, for photodiode scanning to obtain colour-dependent intensity signal

摘要

A dye indicator undergoes a colour change on attaining a predetermined concentration of acid vapour. A housing is insertable in an aperture (21) of the film container (20). The indicator (50) can be placed inside the housing and be in gaseous contact with the interior of the film container (20) via a bore (12). A lens (40) set in a window port (14) in the housing (10), is spaced apart from the indicator (50). USE/ADVANTAGE - For monitoring exposed photographic film stored for long periods at ambient temperature in closed film cans, and which decomposes with formation of acid vapours, eg condition of old (cellulose ester) photographic film, e.g. archive cinematographic films. Allows colour indicator-strip to be viewed, without opening film storage can and also to be monitored by automated system.