In this new series light sources, surface characteristics and visual stimuli are characterized by unified profiles. Information about unified profiles to describe spectral data you can find here.
Below two phosphor-converted white LEDs are compared. Light with a Correlated Color Temperature of 4000K causes usually a more cool and bluish impression than light with a CCT of 3000K.
For wayfinding signage it is essential that the sign is conspicuous and that the messages it contains are legible. This study investigated the optimal luminance for internally lit wayfinding signs in Swiss railway stations. The results demonstrated first, that increasing the light output of the LEDs inside the sign improved conspicuousness of the signage against its surroundings, and second, that considerable improvement of the signage’s legibility could only be observed until its white text reached a luminance of 100 cd/m2. Hence, for internally illuminated signage in general indoor situations, a luminance of 100 cd/m2 is recommended. Very high luminances should be avoided because even if conspicuity is improved, legibility might worsen.
Recent work concerning preferred LED lighting for interior materials was presented at the AIC conference in Tokyo. Therewith an earlier publication „Influence of lighting conditions on the appearance of typical interior materials“ is followed up. Preferred visual appearance iswas accessed for a set of 12 colors taken from the Natural Color System (NCS) catalog and a set of 8 types of wood surfaces. The results of the study demonstrates that certain hues fit better to lighting with higher correlated color temperature (cooler light) and other hues fit better to lighting with lower CCT (warmer light). The observed reactions to wood surfaces lead to the assumption that mainly hue determines the correlated light temperature of the LED light source that is preferred.