Museum lighting must use a light source suitable for preserving the colours of the objects being lit. This paper examines how prolonged exposure to three light sources typically used in museums affect the chromaticity of five pigments commonly used in Chinese traditional heavy colour painting. The three light sources were tungsten halogen with an infrared filter, metal halide and an RYGB-type LED. The chromaticities of the pigments were measured at regular intervals over 1152 hours of exposure. These data were used to reveal the chromaticity shifts occurring and hence the relative effect of each typical light source. Of the three light sources measured, the RYGB-type LED had the least chromaticity shift, on average. These results provide a database for related research on Chinese traditional heavy colour painting illumination and provide a more general reference for the choice of light source in the design of museum lighting.

Optical radiation can cause permanent damage to the colours of high-responsivity Chinese traditional paintings. The white light emitting diode is flexible, efficient and can create similar colour phenomena with different spectra, making it easy to adjust the spectral irradiance distribution according to specific requirements. It is important to establish quantitative influence rules of white light emitting diode narrowband light for protecting traditional paintings, which optimises the constitution and proportion of the white light emitting diode spectrum according to the lowest damage level. In this study, we utilised typical narrowband spectra as light sources to illuminate Chinese traditional heavy colour paintings, and measured the CIELAB colour data periodically. We then calculated the colour difference based on the data and drew corresponding decay curves for the different pigments used. By analysing the quantitative influence characteristics, we were able to determine the quantitative influence and relative influence coefficient of each narrowband light type. These results provide a reference for the spectral irradiance distribution of the minimum-damage white light emitting diode for different heavy colour painting types based on the inorganic pigment characteristics.