This study investigates colour harmony in visual experiments in order to develop a new quantitative colour harmony model. On the basis of new experimental results, colour harmony formulae were developed to predict colour harmony from the CIECAM02 hue, chroma, and lightness correlates of the members of two-or three-colour combinations. In the experiments, observers were presented twoand three-colour combinations displayed on a well-characterized CRT monitor in a dark room. Colour harmony was estimated visually on an 11 category scale from 25 (meaning completely disharmonious) to þ5 (meaning completely harmonious), including 0 as the neutral colour harmony impression. From these results, mathematical models of colour harmony were developed. The visual results were also compared with classical colour harmony theories. Two supplementary experiments were also carried out: one of them tested the main principles of colour harmony with real Munsell colour chips, and another one compared the visual rating of the new models with existing colour harmony theories.
The CIE colour rendering index (CRI) has been criticized for its poor correlation with the visual colour rendering of many spiked or narrowband sources, its outdated colour space and chromatic adaptation transform and the use of a small number of non-optimal reflectance samples that have enabled lamp manufacturers to tune the spectrum of a light source to yield, in some cases, inappropriately high general CRI values. The CRI2012 metric proposed in this paper addresses these criticisms by combining the most state of the art colorimetric colour difference model, i.e. CAM02-UCS, with a mathematical reflectance set that exhibits a highly uniform spectral sensitivity. A set of 210 real reflectance samples has also been selected to provide additional information on the expected colour shifts when changing illumination.
The colour rendering index was introduced at a time when a second generation of fluorescent lamps was being brought onto the market. Today a new generation of light sources based on LED technology is becoming available, so it is opportune to consider whether the colour rendering index is applicable to these relatively new sources. In the present work a series of visual colour rendering investigations are described and their correlation with the current method of calculating colour rendering index as well as with possible updates of the calculation method is evaluated. Visual experiments have shown that the CIE Test Method is not a good predictor of visual perception. A method based on calculating colour differences using the CIECAM02 colour appearance model provides better correlation between visual and calculated colour rendering values.
This study describes the development of a new measure intended to improve the description of light source colour quality. Previously, the authors have developed several colour harmony formulae to describe observers' impressions of colour harmony for two- and three-colour combinations seen under well-defined viewing conditions. One of the applications of these formulae is to quantify the distortion of colour harmony that can occur on changing from one light source to another. Based on the colour harmony predictions of these formulae for a sample set of colours seen under reference and test light sources a new light source colour quality metric, the `colour harmony rendering index', is defined. Two experiments were carried out to investigate the correlation between visual observations and this new colour quality metric.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.