Semantic resonance to light sources of different correlated colour temperature

New light sources are nowadays used as a consequence of energy saving problems and developments of illumination technology. Their quality is evaluated in terms of their rendering capabilities and of people preferences. The research is focused on the psychological reaction of young participants to the environmental lighting of three rooms expressed by subjective measures of a list of associable qualities. We then describe how observers can distinguish different qualities of interior lightings. One room was lighted by a halogen lamp, and two other rooms by LED lamps. Walls were white and a rather large coloured Mondrian was hung at a wall. A group of 370 high school students volunteered in the experiment. Their task was to evaluate the quality of the three illuminations by using a semantic differential. Evaluations were performed in small groups or individually, and data were collected for each participant. Many students left the experiment after performing their task in one or two rooms only. Therefore, data from 197 students who completed the task in all the three rooms were considered. An ANOVA shows that the halogen lamp receives evaluations significantly different from the other two light sources. The two LEDs received equal evaluations in seven scales and significantly different in other three scale. A factorial analysis identifies three factors; in relation to all of them the halogen lamp significantly differs from the LEDs, while the two LEDs differ one from the other only in two factors. In conclusion naive young participants can consistently evaluate personal psychological reactions to lights and discern the qualitative features of the lightings; evaluations are not consistent with the differences in CCT of the three sources but seem affected by other lighting characteristics; some evaluations seem to depend on participants’ psychological context.