Further Observations of Ozone and Nitrogen Dioxide Pre-Dosed Digital Prints Over Time

Abstract

There have been numerous reports on the effects of atmospheric pollutants on digitally printed materials that describe fading of colorants, yellowing of substrates, colorant bleed, and delamination of the ink-receiving layer on some digital prints. In 2010, the Image Permanence Institute published the results of an experiment on the effects of ozone and nitrogen dioxide on various digital print types. While it was not the intent of that experiment to determine the longterm effects of pre-exposure to pollutants, it was discovered after publishing the research that some of the samples dramatically yellowed while in storage. This research studied how those same digital prints stored at controlled room conditions changed after being exposed to ozone or nitrogen dioxide prior to storage. The yellowing of papers exposed to ozone before storage was previously documented in studies directed toward the development of test methods for accelerated aging. This paper documents real-time observation of digital prints after several hundred days in storage and addresses the potential damage to digital prints over time after exposure to ozone or nitrogen dioxide. The test samples included inkjet, color and black-andwhite electrophotography, dye sublimation, digital press, chromogenic, and offset lithography prints. Paper yellowing, colorant change, further colorant bleed, and additional disintegration of the colorant layer of some prints were observed. Porous-coated materials exposed to ozone yellowed more dramatically in storage than when under direct exposure. This illustrates that initial results of change in these materials do not describe the whole story.