Abstract
Colour constancy is the perceptual stability of object colours under changes in the incident illumination spectrum, but it is known to be imperfect. For paintings displayed in museums, the inconstancy of colour appearance under changing illumination influences both appreciation and interpretation. Previous studies of viewers' preferences under restricted viewing conditions have demonstrated that the correlated colour temperatures (CCTs) of preferred illuminations differ from the typical museum standards (e.g. Nascimento and Masuda 2014). Here we examined how the preferred illumination chromaticity depends on the individual viewer, the painting's image statistics and pictorial content, and the overall lux level. Participants (n=16) viewed single paintings in immersive lighting provided by multi-channel LED light sources whose output spectra they controlled in real-time using joystick buttons, freely traversing all chromaticities achievable within a given lux level and which satisfied a spectral smoothness constraint. Selected illumination chromaticities were averaged over four runs, each starting at a distinct randomly selected chromaticity, for each of 5 lux levels, in separate blocks for each of 3 figurative 19th and 20th century paintings. Each block was preceded by a two-minute dark adaptation period. Results: The chromaticity of the preferred illumination depends on the lux level, individual participant and painting. Despite individual variation in settings, the preferred illumination chromaticity correlates with the mean painting chromaticity (under white light), suggesting that participants might be matching the illumination implicit in the painting.
Meeting abstract presented at VSS 2018