Colour fidelity for picture gallery illumination, Part 1: Determining the optimum light-emitting diode spectrum

Abstract

Colour rendering for picture gallery lighting means colour fidelity, showing the colours of the pictures as seen by the painter in the light he used in creating the pictures. As up to the beginning of the 20th century illuminance high enough for good colour vision was possible only in daylight, daylight would be the optimum illuminant. For art preservation and energy saving reasons this is not feasible. Museums often use light of 3500 K correlated colour temperature (CCT). A method is described that takes chromatic adaptation into consideration to determine the spectral power distribution producing least colour distortion of object colours while changing from a higher adaptation luminance at 6500 K to 3500 K illumination at a lower adaptation luminance. The method can be used for any CCT and adaptation luminance values.