Lighting spectrum to maximize colorfulness

Abstract

The spectrum of modern illumination can be computationally tailored considering the visual effects of lighting. We investigated the spectral profiles of the white illumination maximizing the theoretical limits of the perceivable object colors. A large number of metamers with various degrees of smoothness were generated on and around the Planckian locus, and the volume in the CIELAB space of the optimal colors for each metamer was calculated. The optimal spectrum was found at the color temperature of around 5.7×10(3) K, had three peaks at both ends of the visible band and at around 510 nm, and was 25% better than daylight and 35% better than Thornton's prime color lamp.

Effects of high-color-discrimination capability spectra on color-deficient vision

“…The CIE illuminants [28] included D illuminants with correlated color temperature (CCT) in the range of 25,000-4000 K synthesized from Judd's daylight spectral basis functions [29], illuminant A, C, D65, E, F11, FL3.7, and HP1. The high-color-discrimination illuminants included two reported before: the prime-color illuminant derived by Thornton [6,7], with spectral bands at 430, 530, and 660 nm, and the one derived by systematically computing the volume of the Rösch-MacAdam solid obtained with sets of metamers with chromaticities at and around the Planckian locus, whose spectral bands had three peaks at both ends of the visible band and at 510 nm and the chromaticity CIE 1931 (0.32, 0.34) [27]. Hereafter, this illuminant is called Masuda and Nascimento's.…”

“…Table 1 shows the Rösch-MacAdam volumes of the spectrally optimized illuminant obtained here [spectrum represented on Fig. 1(c)], of the illuminant derived by Masuda and Nascimento [27], and of the prime-color illuminant. Unlike the prime-color illuminant, the other two illuminants show a volume that is considerably larger than the maximum produced by daylight.…”

“…Figure 4 shows the spectral profile of the three-band illuminants: (a) prime color, (b) Masuda and Nascimento's, and (c) spectrally optimized, and the corresponding Rösch-MacAdam color solid. The comparison between daylight and the prime-color illuminant was carried out in the analysis reported in [27].…”

“…Three high-color-discrimination illuminants were tested: one suggested by Thornton [6,7], the prime-color illuminant, with spectral bands at 430, 530, and 660 nm; one with peaks at both ends of the visible band and at around 510 nm, which was proved to be 25% better than daylight and 35% better than Thornton's prime-color illuminant [27]; and one derived here by maximization of the Rösch-MacAdam color solid. The methodology to assess the effects on color-deficient observers was to compute and compare the Rösch-MacAdam color volumes rendered by these illuminants for dichromatic and anomalous trichromatic vision.…”

Controlled angular redirection of light via nanoimprinted disordered gratings

“…The findings are presented in the context of daylighting [11,12] through windows, i.e., optimizing the path of sunlight for improved natural indoor lighting, although the method can be generalized and adapted to a number of applications that include color-controlled lighting in optical systems [13] and optical sensing [14].…”