The Photographic Activity Test (PAT) was developed by the Image Permanence Institute of the United States to test the quality of photographic storage materials. It is the subject of International Standards Organisation standard ISO 18916:2007 Imaging materials – Processed imaging materials – Photographic activity test for enclosure materials.
The previous standard ISO 14523:1999 describes the test as a 'predictive test of interactions between storage enclosure[s] and photographic image[s]. It can also be used to evaluate possible photographic activity caused by components of enclosures such as adhesives, inks, paints, labels, and tape.'
Put simply, the test indicates whether a material is likely to damage photographs, negatives, slides, motion picture films, etc. The test looks for chemical interactions that manifest as discolourations of photographic material. If a product fails the test, it should not be allowed near photographic materials.
To carry out the PAT, samples of the enclosure material to be tested are stacked into a 'sandwich' held in a stainless steel jig. A second control sandwich is prepared using a known good enclosure material. Samples are then incubated in a temperature and humidity-controlled chamber at 70 °C and 86 per cent RH. If after 15 days the detectors incubated with the test enclosures are either more faded, much less faded or are more stained than those incubated with the controls, the enclosure material fails the test. Fading and staining are measured using a high quality photographic densitometer. The pass/fail limits are derived from enclosures that actually cause fading or staining in real-life storage situations.
Regardless of claims made by manufacturers or suppliers about the archival quality of their products, do not assume that these products have been subjected to a PAT or that they have passed the test. The PAT is quite separate from, and additional to, normal notions of archival quality.
Products bearing the National Archives Archival Quality trademark are exceptions to this rule. These products have passed the PAT.
The National Archives of Australia is committed to ensuring the quality of products used for storing archival materials. As part of this commitment the National Archives will test any product submitted by a user or manufacturer which is designed to store archival photographic material safely.
Products that have already been subjected to a PAT are listed in the table below . More products will be added as they are tested.
- The test results reported here are intended for general information and do not imply an endorsement of any manufacturer, supplier or product cited. Professional advice should be sought before applying the information to particular circumstances.
- The results given here necessarily apply only to the specific samples tested at a given time by the National Archives of Australia. Each run of paper, board, plastic, etc from a given mill or manufacturer can, and probably will be different. Therefore, National Archives test results may not be applicable to products ordered from the same suppliers today.
- From the beginning of 1999 the National Archives paper testing facility was accredited by the National Association of Testing Authorities (NATA) to carry out a range of tests including the PAT. Testing after that date has therefore been carried out to the standard required by NATA. Before 1999 testing was carried out according to the ISO standard but without NATA accreditation.