What Does PAT Mean When Buying Photo Storage Materials?
By ImgHeal · Updated
PAT means Photographic Activity Test, a test used when assessing materials that may contact photographs. Ask suppliers for photograph-specific specifications rather than relying on the word archival. A suitable tested enclosure still needs to fit the object and its condition; the label does not certify a homemade storage arrangement or make every plastic appropriate.
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Check the product specification
Read the exact item description and retain a copy of the supplier's statement. The Library of Congress connects photo-safe enclosure selection with ISO requirements including PAT. Do not assume that a supplier's entire range has the same properties as one tested product. Ask what material touches the image, whether coatings or adhesives are present, and whether the claim applies to the actual size and product being ordered.
Match the enclosure to the photograph
Identify whether you are housing an ordinary stable paper print, a fragile surface, a glass object, or film. Different materials and conditions need different choices. A transparent sleeve can improve access but may be inappropriate for a damaged image surface or certain negatives. Do not slide a lifting or sticky photograph into a tight sleeve merely because the packaging lists a favorable test result.
Keep a decision record
Write the product reference beside your rehousing notes and test the physical fit using a harmless paper template first. Leave enough support around edges without allowing loose movement. Keep the original housing and its useful labels until they have been documented. If the object's process or condition is uncertain, ask a photograph conservator for a recommendation before buying a large quantity or changing the entire collection's housing.
Before you finish
- The claim applies to the exact product.
- The material suits the object's condition.
- Fit and supplier details are recorded.
Sources and further reading
- Image Permanence Institute: Photo-safe Material TestingIndependent laboratory information on PAT and the other tests used to assess photo-storage, display, and labeling materials.
- Library of Congress: Care, Handling, and Storage of PhotographsPhotograph-specific guidance on enclosures, handling, storage orientation, and materials that can harm images.
Questions about this restoration task
Does PAT mean an enclosure will preserve every photograph?
No. Material compatibility is only one part of storage. Object condition, enclosure design, fit, and the storage environment still matter, and some photographic processes need specialist advice.
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