Spectral reflectance and chromaticity differences of various colors of interior finishing material samples under tunable LED lamps

Abstract

The appearance of objects in interior lighting scenarios is determined by spectral characteristics of the light sources and of the interior finishing material surfaces. Within recent developments of tunable LED lamps, it is possible to vary the correlated color temperature (CCT) of the sources; however, it is relatively unknown whether such variations shall also shift the color appearance. Therefore, this study aims to identify and to analyze the spectral reflectance and chromaticity differences of various colors of interior finishing samples under a tunable LED lamp with varying CCT. The chromaticity coordinates were estimated from the spectrally reflected exitance, under the CIE standard illuminant E and a tunable LED lamp with 10 CCT values (2000–6500 K). Ten samples of painted plywood and wallpapers of various colors were tested. Spectral reflectance of the painted plywood and wallpaper with yellow, beige, red, pink, brown colors can be accurately measured under the tunable LED with CCT 5000 K. Meanwhile, dark blue, dark green, light green, gray, light gray colors are best to be measured under CCT 5500 K. The smallest difference of chromaticity coordinate (Δu'v' = 0.117) is obtained for the light green color sample, meaning that its color appearance is the least likely to change when illuminated by LED lamp with varying CCT. The key contribution is the method to determine the characteristics of interior finishing materials with different colors, observed under tunable LED lamps. The findings can be applied as guideline to optimize objects color appearance in various interior lighting scenarios.