The use of luminous colors is increasing in design and art due to new technologies in color-tunable lighting. Our project addresses the lack of guidance when working with additive mixing of luminous colors, including their interaction with surface treatments. When using paint colors, designers and artists can draw from theories developed by both color scientists and artists/designers.

However, the same is not yet true when working with additive mixing of colored light, which LED technology only recently made possible. The project’s overall scope was to explore and identify various aspects in the use of luminous colors from a perception-based perspective, and to develop and propose a basis for a perception tool box for practitioners.

Nowadays, lighting planning is predominantly determined by the need to meet physically measurable requirements that are often based on current lighting standards. However, meeting the minimum technical requirements of the standards is no guarantee for a visually appealing light environment. Instead, requirements based on perceived light qualities also need to be included to achieve better user comfort. Taking perception-based qualities into consideration when creating a light environment is, for many, not an easy task. In addition, a common terminology for perceived light qualities is currently lacking, both in industry and in research. The aim of this paper is, therefore, to explore how perceived light qualities of white light sources can be described when employing user-centric measures. The focus was on the qualities of light colour and diffuse and distinct light since these qualities have a great impact on the visual impression of light. The perception was assessed by applying analytical sensory analysis to lighting products, a method found to be promising in previous work. The methodology is based on analytical measurement by the human senses, which is particularly valuable when developing a general terminology. Since sensory analysis is still quite new to the topic of lighting, the applicability of using the methodology to assess lighting in a real context was also investigated. The results of the studies showed that the perception of light qualities can be described using further concepts in addition to those currently used. For light colour, the concepts of reddish, bluish, yellowish, and greenish light colours proved suitable for providing a richer description of the quality. The concepts of diffuse and distinct light satisfactorily captured variations in light contrast produced by shadows, reflections, and sparkles. In addition, the studies revealed that analytical sensory analysis was applicable for assessing the perception of lighting in a real-world context. The latter means that knowledge gained in the laboratory can be translated into real environments. The user-centric measures investigated in this paper have contributed to the terminology related to perceived light qualities. These can complement the physical measures in lighting planning to promote light environments that are not only energy efficient and meet technical requirements, but also cater for increased user comfort. © 2023 by the authors.

Perceived light qualities of lighting products are generally insufficiently described, reflecting that perception-based qualities, such as light colour, are not considered to the same extent as physical measures when creating light environments. It is well known that perceptual impressions are affected by, and relative to, surrounding stimuli. To develop descriptions of perceived light colour of white light sources, new concepts were evaluated in a pilot study combining paired comparison tests and descriptive sensory analysis. The findings confirmed that the perception of light colour is relative, demonstrated by cool light sources being perceived as warm/yellowish/reddish in relation to other cool light sources – which was well captured by the combined sensory methods with simultaneous light sources. The newest concepts, cyanish and magentaish light colour, were found to be useful in describing the perceived differences, showing that more concepts than warm, neutral and cool are needed for a richer description of light colour.