Lightness And Luminance: Perceptual Qualities in Conditions Of Simultaneous Contrast

Abstract

This article is devoted to the research of the influence of induction and crispening effects on the lightness of objects. The target of this research is to simplify and clarify the analysis of the light distributions derived from the results of lighting calculations and measurements, and also to form the recommendations for obtaining preferred lightness contrasts in the case of visual perception of objects on different backgrounds. To provide such possibilities, it is necessary to refine the model of the lightness calculation in modern colour appearance models, which, in turn, requires the results of new experiments to take into account the induction and crispening effects in the conditions of simultaneous contrast. The same experiment was established by Takasaki on visual perception of grey squares on grey backgrounds. The article substantiates the necessity to refine the results of the Takasaki experiment and conduct the new experimental approach in more strictly specified conditions and in the expanded luminance range to ensure conditions of the modern standards. Here we propose setting up an experiment that provides these refinements and considers the properties of the proximal field – the contour of objects. The search of the results uses multi-objective optimization methods. The first results of this experiment are presented, based on them, were formed proposals to determine the preferred luminance of objects to ensure the required levels of lightness contrast when working on specified backgrounds. The calculations of the lightness deviations obtained as the result of the experiment and in the CIECAM02 colour appearance model, are presented. The peculiarities of translations of lighting engineering literature in the field of modelling a light-colour environment are noted, which require clarification for a correct and reliable understanding of colour appearance models, for which is proposed to open a discussion on this subject.