LAUSR

Abstract In sensory practice, the color masking procedure is executed almost exclusively with red light, regardless of the color of the product. In this work the practical application of a novel approach for sensory masking of color differences, hence the applicability of a spectrally tunable light booth was investigated. The aim of the research was to find the most appropriate masking environment, which i) can be considered as the most effective mask and ii) provides the best conditions regarding chromatic adaptation. The main idea of the novel approach in sensory color masking is that the instrumental characterization of all parameters influencing the perception of the sensory assessor. The comparison of the potential masking illuminations based on instrumental results (considering masking effect and chromatic adaptation) and the definition of the most appropriate mask should be accomplished based on sensory tests. The sensory effects of colored environments were tested on chocolate samples containing different amount of cocoa. CIELAB dE color differences between the samples were calculated based on their spectral reflectance. Four monochromatic (red, green, blue, amber) and six combined masking illuminations were developed in a spectrally tunable light booth and were instrumentally characterized by their spectral power distribution and luminance values. The chocolates were ranked according to their darkness by the assessors. The masking environments were compared based on the analysis of sequence correctness, decision time, and their combination (ANOVA, Survival-analysis). In Experiment 1 the monochromatic Blue light was not only more effective, than the commonly used Red light, but it was the most effective mask regarding color differences: the sequence error increased to 61% compared to the standard white (D65) illumination, and the decision time increased to more than double (15.74 s → 35.7 s). In Experiment 2 green and amber lights were combined with the blue mask, increasing the degree of chromatic adaptation: decision time decreased while the effectiveness of the mask did not decrease based on the sequence errors. Following the novel approach product specific masking environment considering effectiveness and chromatic adaptation was realized verified by statistical analysis of sensory test results.