Blemish Formation in Processed Microfilm II

Area of Science:

• Archival Science
• Material Science
• Preservation Science

Background:

• Gaseous peroxides can cause blemishes on processed microfilm.
• Microfilm degradation is a critical concern for long-term information preservation.

Purpose of the Study:

• To investigate the susceptibility of processed microfilm to blemish formation.
• To identify factors influencing microfilm blemish formation and stability.

Main Methods:

• Two testing procedures were developed using peroxide paper and zinc powder to assess blemish susceptibility.
• Microfilm samples were conditioned at 86% relative humidity and 26°C.
• Different grain sizes (coarse vs. fine) and fixing agents (ammonium thiosulfate vs. sodium thiosulfate) were evaluated.
• Oven-aged storage cartons were tested for peroxide generation.

Main Results:

• Microfilm susceptibility to blemishes decreased under specific humidity and temperature conditions (86% RH, 26°C).
• Coarse-grain microfilms exhibited lower susceptibility compared to fine-grain microfilms.
• Fine-grain microfilms fixed with ammonium thiosulfate showed less blemish formation than those fixed with sodium thiosulfate.
• Wetted, oven-aged microfilm storage cartons generated peroxide, which the microfilm base readily absorbed.

Conclusions:

• Environmental conditions, microfilm grain size, and the fixing agent used are critical factors in preventing microfilm blemishes.
• Storage carton materials can be a source of peroxides, contributing to microfilm degradation.
• Understanding these factors is essential for improving microfilm preservation strategies.