Colour rendering indices are regarded as characteristics of a light source. The paper shows that the environment, where the lamp is used, has a major impact on the observed colour rendering. It is suggested that in selecting a light source for an environment the characteristics of the wall paint should be considered and selected accordingly. It is possible to achieve a higher average colour rendering index, as determined for the lamp alone if the source and paint are properly selected.
Laszlo Neumann, Janos Schanda, "Effect of Interreflections in a Room on the Colour Rendering of Light Source" in Proc. IS&T CGIV 2006 3rd European Conf. on Colour in Graphics, Imaging, and Vision, 2006, pp 283 - 286, https://doi.org/10.2352/CGIV.2006.3.1.art00057