Assessment of the Current Light-Fade Endpoint Metrics Used in The Determination of Print Life – Part I

Abstract

Print life estimation of consumer prints has historically been based on endpoint criteria defined in terms of changes in density (loss of density). This methodology has served the conventional silver halide community well for many years. The robustness of these endpoints for several new output technologies (thermal dye transfer, ink jet, electrophotographic) was evaluated. Also, how well the current endpoints correlate to customer judgment of print acceptability is evaluated. This paper will discuss a psychophysical study conducted to determine if the current metrics, based on changes in density, are robust over several technologies and correlate well with customer judgments of print acceptability. Eight output systems from six distinct output technologies were used to assess the current endpoint criteria. Customer judgments of 16 scenes at 25 levels of degradation were correlated to objective metrics based on densitometric measurements of color tonescales. The data show that the current endpoint criteria are not robust over the digital output systems included in this study when compared to the results of the psychophysical study and are therefore inadequate for comparing print life estimates across the various digital output technologies.