As we all know, CIE color rendering index (CRI), especially the general color rendering index Ra, widely used in the lighting industry, is an international and domestic standards and technical specifications used to evaluate the color of light an important indicator. However, in recent years, with the development of solid state lighting, CRI defects gradually highlighted, in many cases the value of Ra and the general observer can not match the visual assessment, mainly in two aspects: First, can not accurately characterize the color Truth; second is the lack of color quality perception related to the evaluation. So the CIE decided to adopt a better characterization method to measure and regulate the color quality of white light sources, the work is divided into two parts, by the TC1-90 responsible for the development of more scientific and accurate color fidelity indicators, by TC1-91 Fidelity outside the color perception related to the indicators.
The technical report CIE 224 is the result of TC1-90, and the color fidelity of CIE 2017 is proposed, which is general color fidelity index (Rf). This indicator is based on the fidelity index defined in TM-30-15 of the North American Illuminating Engineering Society, which mainly corrects the inaccuracy of CRI as a color fidelity index.
Rf is the average of the degree of color appearance of all swatches under the illuminated and reference light exposure, similar to the general color rendering index Ra, but it only considers one aspect of the color quality and does not take into account the visual perception / preference Wait. So at this stage Rf can not replace the CRI, CRI alternative is to study and discuss the subject, in addition to Rf, but also the development of a series of new perception related to the color quality indicators.