Image Storage and Long-term Preservation

PAT TestIn the early 1980s, soon-to-be IPI director, James Reilly, was asked by ANSI to develop a new test that would accurately determine whether a given storage enclosure material would harm photographs. Experimental work ultimately lead to the development of the Photographic Activity Test or PAT, which became an ANSI and then an ISO standard and remains a trusted method for determining the safety of a material used in photo storage or display. IPI has continued to improve the accuracy of the test and to expand its scope to include plastics, adhesives, inks, and other materials. Staff is currently determining if the PAT can be applied to the many digital print types available.

In 1997, there were no guidelines or accepted standards for determining the level of image quality required in the creation of digital image databases for photographic collections. Research undertaken by IPI led to the development of an image quality framework to help in planning digital imaging projects, published in Digital Imaging for Photographic Collections: Foundations for Technical Standards by Franziska Frey and James Reilly.

In 2007, IPI embarked on a three-year study to develop an understanding of how digitally printed materials will behave during long-term storage, on display, and when handled. Inkjet, electrophotographic, and dye sublimation digital images have been exposed to heat, moisture, pollution, and light. The prints were also subject to handling stresses, potentially unsafe enclosures, and flood. Results of this research will be published in professional journals and distilled into care recommendations posted at IPI's Digital Print Preservation Portal (DP3) website,

IPI studied the effects of common air pollutants—ozone, nitrogen dioxide, sulfur dioxide, and hydrogen sulfide—on the types of photographic films most often used in micrographic applications in library collections.  Additional research studied the reactions of color and black & white prints and films to lower concentrations of pure pollutant gases at controlled temperature and humidity and the possible mitigating effects of enclosures against damage from atmospheric studies. Among other results, enclosures were found to provide some protection to microfilm materials, but supplementary HVAC and air filtration is still needed to effectively avoid pollutant damage.

In the late 1990s, IPI was one of several testing facilities to study pollution and paper stability. IPI's assignment was to develop an aging test that would evaluate a paper's susceptibility to decay by atmospheric pollutants and to find a pollutant test method that would reflect predictable behavior over the long term. IPI's test results provided the information required to establish a standard paper/pollution test procedure.