Dim-to-Warm Lighting: An Experimental Analysis of Preference and Perceived Naturalness

<p>LED luminaires that produce a shift to a lower correlated color temperature (CCT) when dimmed to mimic the dimming of an incandescent lamp are marketed as “dim-to-warm.” Despite the commercial popularity of “dim-to-warm” lighting, most academic research, to date, shows no significant preference for a reduction in CCT when lighting is dimmed. A controlled laboratory experiment was conducted where participants were exposed to a range of dynamic lighting conditions that shifted CCT as the lighting was dimmed.

Participants were asked to rate each lighting condition as soon as the dimming ended, before visual adaptation was complete. Likert ratings for “preference” and “naturalness” were recorded, the experiment being repeated for work and social scenarios. The same conditions were rated using both manual and automatic dimming modes.