“Virtual Fading” of Art Objects: Simulating the Future Fading of Artifacts by Visualizing Micro-Fading Test Results

Abstract

The authors examine the importance of visualizing the color changes of colorants exposed to visible light, and use this information to create a “virtually faded” art object. The color information collected during lightfastness measurement (as CIE L*a*b* values) with a micro-fading tester can be transformed to RGB values, and color swatches representing the original and faded colors displayed on a computer monitor. Such demonstration of the appearance changes can help to visualize the degree of color change and the precise nature of that change, which may not be simple lightening of the color but could also include hue or chroma changes. Judging the visual impact of a light-induced color change requires viewing the altered color in its context within a particular image. Digital renderings of paintings were created with Adobe Photoshop and Matlab, using a number of fugitive colors, the fading characteristics of which had been recorded with prolonged microfading tests of 100–1920 minutes in duration depending on the light dosage required for the color to no longer be changing. Based on this information describing the appearance of each of the colors as it changes with light exposure, simulations of the “virtually faded” painting were generated, representing the image appearance with incremental light exposure. Such virtually faded simulations can offer insight into the severity of particular light-induced color changes, allow targeting of crucial color areas that might warrant tracking in a color monitoring program, and inform discussions about the “end of exhibition life” of an object and appropriate exhibition rotation policies.