Simulating Accelerated Commercial In-Window Display: Predicted print longevity for pigment ink systems on a range of media types

Abstract

The digital printing industry has largely adopted a standard approach to predicting print life for nominal indoor conditions (i.e. no direct sunlight, potentially glass-covered print). However, currently there is no standard calculation method in wide use for Indoor, “In-Window” display longevity estimates. The actual location of the print could be directly in contact with the window, or near the window (within a meter or two); what these “In-Window” displays have in common is a very high average light intensity—with cyclic exposure—and strong UV spectral component. Thus, simulation methods need to address these conditions.The accelerated light exposure used in this investigation used high intensity Xenon Arc illumination, with a cycled dark / light exposure at controlled temperatures and humidities using a commercially-available device. Inkjet media substrates included nanoporous photo paper, coated paper, “photorag”, and inkjet-coated canvas; the effect of lamination was also examined. A range of pigment-ink printers were used to generate the prints.Based on an earlier survey by one of the authors of actual commercial in-window display environments in Southern California, a 12-hour average lux assumption of 6,000 lux was used to convert the simulated exposure optical density loss data to a predicted lifetime in ‘year or month’ units. As expected, the results were significantly lower than the predicted lifetimes based on the nominal indoor lifetime estimates based on 450 lux / 12-hour average assumption. Different pigment ink systems showed very different levels of fade resistance; lamination was found to potentially increase resistance to fading by a significant factor.