Affective & Human Factors EngineeringThe purposes of this research are to identify relation between color perception and connotation of unrelated colors, and to develop mathematical models for color connotation. This research is significant in the sense that it provides fundamental data for color appearance and color connotation of unrelated colors on which there is a lack of research until now. To achieve these purposes, two psychophysical experiments were carried out.
Experiment 1: Color perception for unrelated colors, to investigate color perception for unrelated color using the 50 color stimuli beamed through a square hole. Twenty-two observers have answered their perceived magnitudes of three color attributes based on the magnitude estimation.
Experiment 2: Color connotation for unrelated colors, to examine color connotation for unrelated colors using the 50 color stimuli. Thirty-two observers have answered their connotation about each color stimulus using the 10 color connotation scales which consist of one aesthetic scale (i.e. ???like ??? Dislike???) and nine non-aesthetic scales (i.e. ???Warm ??? Cool,??? ???Heavy ??? Light,??? ???Modern ??? Classical,??? ???Clean ??? Dirty,??? ???Active ??? Passive,??? ???Hard ??? Soft,??? Tense ??? Relaxed,??? ???Fresh ??? Stale,??? and ???Masculine ??? feminine???). Semantic differential method was used for measurement of color connotation scales.
The color connotation models having brightness, colorfulness and hue obtained by CAM97u and the revised CIECAM02 as input variables were developed to quantify inter-relation between the color attributes and color connotation space, and further effects of the color attributes on color connotation were visually analyzed based on conventional bubble charts.
The major findings from the experiments are summarized as follows:
In experiment 1: Color perception for unrelated colors, the experimental results shows that the three perceptual attributes of unrelated colors such as brightness, colorfulness and hue can be estimated by the colorimetric properties of color stimuli (i.e. luminance, excitation purity and CIE 1976 hue-angle). It is found that the estimate values of the color attributes are positively proportional to perceived magnitudes of the color attributes. The performance comparison is made of proposed estimation model with CAM97u and revised CIECAM02. The revised CIECAM02 gives the best satisfactory estimations of brightness, colorfulness and hue under photopic vision.
In experiment 2: Color connotation for unrelated colors, the experimental results shows that color connotation of unrelated colors has a three-dimensional space, and the three axes are ???Color solidity,??? ???Color heat,??? and ???Color purity.??? ???Color solidity??? is associated with ???Hard-Soft,??? ???Heavy-Light,??? ???Tense-Relaxed,??? and ???Active-Passive.??? ???Color heat??? is correlated with ???Warm-Cool??? and ???Feminine-Masculine???, and ???Color purity??? has relevance to ???Clean-Dirty??? and ???Fresh-Stale.???
In short, color connotation for unrelated colors is a function of the three color appearance attributes. All the color connotation scales are correlated with the color attributes. Four color connotation scales, ???Warm-Cool,??? ???Heavy-Light,??? ???Active-Passive??? and ???Hard-Soft???, were modeled. The scale ???Warm-Cool??? is associated with hue angle and colorfulness, while significant relation between ???warm-Cool??? and brightness is not found. The other scales are connected with the color difference between the test color and neutral color of which brightness are varied with the color connotation scales. This implies that ???Heavy-Light,??? ???Active-Passive??? and ???Hard-Soft??? have relevance to colorfulness.
Furthermore, the three-dimensional color connotation space for unrelated colors is associated with the color attributes. The significant correlations between the axes of the color connotation space and color attributes are as follows: ???Color solidity??? with colorfulness, ???Color heat??? with both hue angle and colorfulness, ???Color purity??? with brightness.
There is room for further improvement and development in this research. (1) The data sets obtained by this research need to examine repeatability, (2) relationships of color connotations between unrelated colors and related colors is required to be analyzed, and (3) the results of this research should expend into applications in association with emotional lighting.ope
