Mitigation of Pollution-induced Deterioration of Digital Prints through Low-Temperature Storage

Abstract

An IPI survey found that approximately 87% of museums, libraries and archives already have digital prints in their collections and that they are concerned about increasing influxes of these materials. The survey also showed that objectionable deterioration has already occurred to some of their prints including fading, yellowing, color bleed, surface cracking and delamination. In total, 71% of institutions have already experienced deterioration in their digital print collections. Previous experimental research, both by IPI and others, has been able to establish a clear connection between ozone and nitrogen dioxide exposure and each of those forms of decay. Development of effective methods to mitigate such damage will, therefore, be critical to the survival of these objects for future generations. This study was aimed specifically at determining the efficacy of one particular approach, mitigating pollutant damage to digital prints through lowered-temperature storage. Since the deterioration due to pollutants occurs through chemical reactions, it may be possible to slow decay through cool or cold storage.The Arrhenius method was used to predict the times to significant fade or yellowing of prints exposed to 1 ppm ozone or 5 ppm nitrogen dioxide. Test targets were incubated at 25°C, 30°C, 35°C, 40°C, and 45°C at 50% RH for multiple intervals up to 56 days. Cyan, magenta, yellow, and black color patches were monitored using ANSI Status A density for density loss. Unprinted, white areas were monitored using ANSI Status A blue density for paper yellowing. It was found that lower temperature does in fact reduce the rates of decay but not equally for both pollutants. Low temperature was more effective at reducing yellowing caused by nitrogen dioxide than it was at reducing the fade caused by ozone; however, cool or cold storage can clearly mitigate damage and extend the usable life of digital prints in collections.