Association Internationale de la Couleur (AIC). Interim Meeting in Stockholm June 15-18, 2008 Conference Theme: Colour – Effects & Affects. The powers of attraction of chromatic light Markus REISINGER, Ana HUEDO * and Ingrid VOGELS* University of Technology Delft, * Philips Research Europe ABSTRACT Chromatic light in achromatic luminous surroundings has the effect of attracting attention of the perceiver to the area of colored light. How strong this effect is depends on the intensity and spectral composition of the light. A psychophysical experiment was performed to determine the luminances of chromatic light from Light Emitting Diodes that give rise to equal levels of attraction for different hues. 1. INTRODUCTION Light influences how objects and surfaces appear to us visually. We can find the same interior space visually more or less appealing depending on the lighting conditions. The distribution of light in space, in particular, influences to which areas people’s attention is drawn. LaGiusa (1974) found that lighting situations that create a visual focus in classrooms transfer and hold attention more effectively than situations in which there is no such focus. There are many different everyday situations in which there is a need to attract attention. For example, shops use a great deal of spotlights to highlight their merchandise in order to attract customers. This study relates to the design of interior lighting, taking into account factors such as the relationship between people, their surrounding environment and the use of color through the medium of chromatic light. The study explores specifically the use of Light Emitting Diodes (LED) for accent lighting. The main goal is to quantify in different luminous conditions physical measures of light that are perceived as similar in terms of their attraction value. Here attraction value is understood broadly to be the ability of a part of the surrounding environment to arouse visual interest. The power of color to attract attention has been found to depend on three attributes: hue, saturation and luminance. Camgöz, et al. (2004) found that luminance has the strongest influence, followed by saturation, while hue has the least influence on attracting attention. Hopkinson and Collins (1970) as well as Erhardt and Steinmetz (1977) stated that vividly colored surfaces viewed against a neutral background attract attention in a similar way to areas that are more brightly lit. Empirical data suggests that different amounts of chromatic and achromatic light are needed to attract attention to the same degree. According to Flynn, et al. (1988), relative luminances for the same attraction values in an accent lighting situation are lowest for red and highest for yellow. The light stimulus in question was described by Flynn as being saturated in color, but no specific information was given about the light sources used or their chromaticity characteristics. Our study examined whether the results obtained by Flynn can be extrapolated to chromatic light of high saturation, such as that produced by LED sources. As we are specifically interested in people’s spontaneous reactions to visual input from the surroundings, we have also considered whether people’s judgment in terms of attraction value would be affected by them having to perform a drawing task.