De-entangling colorfulness and fidelity for a complete statistical description of color quality.

In this Letter, the main attributes known to affect color quality are treated statistically over a set of 118 spectra representing the current mainstream lighting technology. The color rendering index (CRI) is used to assess color fidelity while colorfulness is used to complement CRI-Ra, supported by the growing evidence that assessment of light spectra cannot overlook color preference inputs. Colorfulness is evaluated by our optimal color (Oc) index, through a code that computes the (MacAdam) theoretical maximum volumetric gamut of objects under a given illuminant for all the spectra in our database. Pearson correlation coefficients for CRI-Ra, the (Y. Ohno’s) color quality scale (CQS) and Oc show a high correlation (0.950) between CRI-Ra and CQS-Qa, while Oc shows the lowest correlation (0.577) with CRI-Ra, meaning that Oc represents the best complement to CRI-Ra and Qa for an in-depth study of color quality.