Mathematical Modeling of Black-and-White Chromogenic Image Stability.

摘要

Agfapan Vario-XL film was faded at various levels of temperature, humidity, light, and fade time to determine the mathematical relationships of these variables and to examine whether interaction occurs between each factor. Light stability of the film was measured, and the Arrhenius relationship was used to predict dark stability at ambient storage conditions. It was found that the amount of fade, as measured as either a change in transmittance or density, could be mathematically modeled with a high degree of correlation. Each independent variable (temperature, humidity, and time) was interactive with the other two variables. Under the specific conditions tested, a significant interaction existed between light and dark fading reactions. For example, both the light and dark cyan dye reactions inhibit each other. However, in the case of the magenta and yellow dyes, a synergistic, or catalytic, effect occurs when light fading precedes dark fading. Agfapan Vario-XL is extremely light stable when irradiated by a conventional enlarger light source. The dark stability compares with some of the least stable chromogenic print films -- a 10% loss in printing density is predicted by Arrhenius extrapolation when the Agfapan Vario-XL is stored at room temperature at 45% relative humidity for five years.