Visual colour rendering based on colour difference evaluations

The colour rendering index was introduced at a time when a second generation of fluorescent lamps was being brought onto the market. Today a new generation of light sources based on LED technology is becoming available, so it is opportune to consider whether the colour rendering index is applicable to these relatively new sources. In the present work a series of visual colour rendering investigations are described and their correlation with the current method of calculating colour rendering index as well as with possible updates of the calculation method is evaluated. Visual experiments have shown that the CIE Test Method is not a good predictor of visual perception. A method based on calculating colour differences using the CIECAM02 colour appearance model provides better correlation between visual and calculated colour rendering values.