Perceptual responses to LED illumination with colour rendering indices of 85 and 97

A light source's ability to render colours and whites is one aspect of lighting quality. Since better colour rendition generally comes with a penalty in luminous efficacy, it is reasonable to consider the balance: Should colour and whiteness rendition be sacrificed to achieve higher efficacy? Here, we investigate perceptual responses under illumination from two sources, a blue-pumped LED with a colour rendering index of 85 (BLED85), and a violet-pumped LED with a colour rendering index of 97 (VLED97). Forty-eight participants completed three experiments. Neutral, red, and pink were preferred under VLED97. Skin rendition was preferred by Caucasians under VLED97; Asians had no preference. Teeth and a white shirt were whiter and more preferred under VLED97. We conclude that the colour and whiteness rendition must be considered on a par with luminous efficacy.