The International Commission on Illumination (CIE), which created and maintains the color rendering index (CRI) standard, recently published a position statement on CRI, its limitations, and whether and how to replace it.
The complete statement is available here. Notable excerpts:
On the limitations of CIE:
“With the rapid uptake of LED lighting, which has greater freedom in spectral design, the need to update the CRI has significantly increased. For some types of light sources, the CIE General Colour Rendering Index, Ra, does not agree well with overall perceived colour rendering.”
On CIE’s action to replace CRI:
“The CIE recognizes that, because the Colour Rendering Index has several significant sources of colorimetric inaccuracy, it should be updated with the latest well-accepted formulae and an improved set of test samples. CIE Technical Committee (TC) 1-90 is already in the process of developing a new improved colour fidelity metric that can update the CRI.
“The CIE recognizes that the colour fidelity metrics including the CRI do not assess other important aspects of the colour qualities of light sources, in particular, those related to colour preference. CIE TC 1-91 is developing a Technical Report on this subject, which will be the groundwork for developing colour preference metric(s).”
On adoption or consideration of IES-TM-30, which proposed a new color rendering (fidelity) metric:
“The CIE encourages further research on these two aspects of colour quality, which may be useful inputs to the current or future work of CIE. In particular, the CIE supports the study of the recently published IES[1] Technical Memorandum TM-30, to which some CIE TC 1-90 members have contributed. This work was recently proposed for consideration in TC 1-90, which voted to make its Rf metric the basis for the TC’s first working draft.”
