Color Naturalness in Museum Lighting: Optimizing Ambient Illuminance and Light Source Parameters for Chinese Freehand Paintings

ABSTRACT Museum lighting for paintings collected in Chinese museums, which represent traditional color aesthetics, must balance both the protection of the collection and the enhancement of visual quality to convey the paintings' value, particularly the perception of color naturalness under varying lighting conditions. This study simulated museum lighting environments in a variable space experimental chamber, using representative cold and warm tone Chinese freehand paintings as experimental subjects. Lighting conditions were varied according to three parameters: ambient illuminance ( E ), the fidelity of the light source ( R f ), and the saturation of the light source ( R g ). Color naturalness scores for the paintings were obtained through a subjective evaluation by 30 participants. The results show that increasing the ambient illumination, that is, reducing the contrast in illumination between inside and outside the display case, helps improve observers' ratings of the naturalness of the painting colors and reduces the impact of R f and R g on these ratings, thereby expanding the range of selectable light source parameters. When ambient illuminance was low, increasing R f improved color naturalness, and a moderate R g value more effectively restored the colors of the paintings. Through multiple linear regression analysis, the model for evaluating the color naturalness of cold and warm tone paintings was established, that is, the color naturalness scores of the paintings could be predicted based on the three lighting parameters. This model provides a scientific framework for optimizing the lighting design of paintings collected in museums, benefiting both the preservation and promotion of Chinese traditional culture.