Practice question · Estimate
Silver-gelatin materials are stored cool and dry. What relative humidity, as a percentage, sits in the middle of the usually recommended band?
Estimate on a scale from 0 per cent (0) to 100 per cent (100).
Hints
- The usual recommendation is a band rather than a value.
- Somewhere between thirty and forty per cent.
Show the answer
35 (answers within ±10 count)
Why
About 35 per cent, with the usual recommendation running from 30 to 40. Both directions are dangerous: high humidity encourages mould and accelerates chemical attack on the silver, and very low humidity makes the gelatin brittle so that the emulsion cracks when the print is handled.
Practise Archival Processing and Permanence
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