There are several characteristic values for evaluating the color rendering of light-emitting diodes(LEDs). In addition to the color temperature, there is the color rendering index(Ra), which reflects the color perception. Other parameters are the Feeling of Contrast Index( FCI) for subjective color perception and the Color Quality Scale (CQS), which is used to evaluate the color rendering of a light source.
Unlike the color rendering index, the color quality scale takes into account some factors such as color differences and human preferences. The CQS value is based on a color scale of 15 normal object colors. The scale, developed by NIST, evaluates a wide variety of aspects of the color rendering of illuminated objects. The CQS value is determined in a similar way to the color rendering index, but based on a color palette of eight more or less saturated standardized color samples.
The color quality scale is a quantitative measurement used to evaluate light sources for illuminating objects.