Colour discrimination in the frame of illuminating engineering. Effects of C and high-pressure Na sources at different illuminances.

Nowadays, people are encouraged to utilize colour information. In turn, the sources employed for both indoor and outdoor installations show a variegated gamut of spectral distributions. The colour rendering factor refers to the average observer, representative of the normal, young, adult, healthy population. In order to have an idea of the deviations from this ideal case, we have been undertaking a population study. The results up-to-date obtained by the use of the high pressure Na source are now briefly reported.