Emotional Evaluation of Juxtaposition Mixtures: The Influence of Value Contrast

Background Juxtaposition mixture is a visual phenomenon in which adjacent color units appear either as a solid color or as a “visually mixed” state depending on viewing distance and array structure. Although colors may share the same mean value, affective impressions can differ significantly according to mixing density and value contrast. However, systematic quantitative comparisons remain scarce. This study aims to compare the affective responses induced by solid colors and juxtaposition mixtures (low contrast, high contrast) and to empirically investigate how value contrast and mixing density modulate affective structures. Furthermore, the study estimates the perceptual threshold of “boundary–integration” balance across density levels, with the goal of suggesting the potential of juxtaposition mixture as an affective design control parameter. Methods Two experimental stages were conducted. In the preliminary stage, stimuli varying in value difference (low/high) and spatial density (25 levels) were presented to determine the threshold at which “boundary perception” and “integration perception” were balanced. In the main stage, affective evaluations were carried out by presenting solid colors, low-contrast mixtures, and high-contrast mixtures. Using 19 bipolar adjective pairs on a seven-point Likert scale, participants assessed the affective impressions of each stimulus. Hue, chroma, and mean value were controlled so that only the effects of value contrast and juxtaposition mixing were tested. Results Even with identical mean value, affective impressions differed significantly between solid colors and mixtures. Solid colors were associated with impressions such as “clear,” “clean,” and “calm,” aligning with stability and preference. In contrast, low-contrast mixtures elicited feelings of “soft,” “quiet,” “natural,” and “warm,” forming a relaxed and nature-related impression. High-contrast mixtures, however, produced impressions such as “rough,” “dense,” “tense,” “noisy,” and “energetic,” delivering strong visual stimulation and vitality. Factor analysis revealed that solid colors formed five factors centered on preference and cleanliness, low-contrast mixtures yielded six factors including naturalness and relaxation, while high-contrast mixtures resulted in four more condensed factors characterized by artificiality, modernity, and arousal. Conclusions The findings confirm that even with the same mean color values, significant affective differences arise depending on value contrast and mixing density. Solid colors tend to induce refined and stable impressions; Low-contrast mixtures promote softness, naturalness, and relaxation; High-contrast mixtures elicit roughness, density, tension, and vigor. Thus, the level of value contrast within juxtaposition mixtures functions as a critical determinant of both the direction and intensity of affective responses. These results suggest that in fields such as architecture, interior design, fashion, and visual communication, incorporating viewing distance (mixing density) and value contrast as design parameters allows for precise modulation of affective experiences without altering mean color. Nonetheless, conditions with static stimuli, further research should include ecological factors such as natural light, material texture, and dynamic viewing, as well as multisensory cues.