Optimizing Light Source Spectra for Art Conservation: Exploring Basic Color Groups

Exposure to light can cause fading, discoloration, and other forms of damage to light-sensitive artwork. Pigments and materials used in an artwork have specific spectral absorption and reflectance properties, determining the wavelength of energy they absorb or reflect. By carefully tailoring the spectral power distribution of the light source, it is possible to minimize the energy that is absorbed by the pigments in a painting. However, individually characterizing each reflectance of a pigment in the painting, optimizing the spectra, and emitting optimized spectra to that area can be highly complex and time-consuming. Grouping similar spectral reflectance shapes and optimizing for a set of representative groups can reduce the complexity and time required for spatial and spectral optimization required for projection mapping technique. This study grouped spectral reflectance of 24 Macbeth ColorChecker samples into four basic groups and optimized the spectra for both individual color samples and four basic color groups. Results indicate that the color grouping approach is 16 times faster than individual color optimization approach with no significant difference in terms of color appearance, energy consumption, or damage reduction from light absorption.