Both Fig. 1 and 2 clearly show that higher values of CRI do not necessarily mean better color quality. Logically then, CRI should never be used by government regulators as a patch to luminous efficacy requirements to ensure that light sources will provide the expected benefit of color quality.
The fundamental problem is not, however, replacing one color quality patch with another one (e.g., GAI). Rather, the solution is to revise the current definition of luminous efficacy that is based upon photopic lumens per watt. The photopic luminous efficiency function, V(λ), sets the wavelength range and the weighting of those wavelengths in the numerator of the luminous efficacy calculation (i.e., lumens). V(λ) was developed in 1924 to represent "the spectral sensitivity of human vision".4It is now known that V(λ) is based on just two of the five photoreceptors in the human retina, the long-wavelength (L) sensitive and the middle-wavelength (M) sensitive cones. The other three retinal photoreceptors provide humans with sensitivity to shorter wavelengths, so V(λ) is an inadequate and incorrect representation of human spectral sensitivity......"
As far as I can remember to have read, the Vlamba curve was made way before they knew which receptors there were in the humen eye, it is an empirical curve made by asking a representative number of people how bright the different wavelengths are perceived. If those experiments in the twenties (?) were performed well, the curve should not change based on what they now know about receptors.
But I guess that when I read the article fully instead of scannning it through, things get more clear to me.
We all know with the same CRI, the results can be totally different to human eyes.
This is another same topic in the search of a much better universal good quality light standard. But the approach researched, is in the correct direction, IMO.
