Improved Dark Storage Test Method

Abstract

The digital print industry is working toward the goal of adopting improved test methods for image permanence. As part of this effort, the new test methods are being designed to isolate the environmental variables that impact image permanence. The benefits of this approach are that it simplifies the test method and test equipment while promoting test results that can be reproduced at other test laboratories. To understand which variables to isolate for a given test method, it is necessary to investigate a broad range of conditions which may affect the test results. These variables may not have been controlled in the past, may be difficult to control, or may not accurately reflect real world conditions. In a prior paper, it was shown that airflow can affect the rate of paper yellowing in a thermal stability test used to simulate dark storage conditions.During that testing, additional sources of potential noise were identified that affected the test results. This paper continues that investigation by showing that the presence of other test samples in the thermal test can influence the results; that is, samples can cross contaminate each other in the thermal test. This paper also details the development of a new test method which minimized the effect of cross contamination of samples within the thermal test. Moreover, the new test method also reduces variation in test results caused by varying airflow, either by position within the test chamber or due to testing in chambers of differing design. This research is part of ongoing work contributing to the development of standardized test methods for image permanence.