This paper shows the research data of psychophysical visual effect of simultaneous contrast when changing RTV of background lightness in the printing process. An experimental research on graphic reproductions made in the offset printing technique with specifically constructed design solutions that cause the above mentioned effect was carried out. Samples were designed as ten various lightness variances of background, with a range from 10% RTV to 100% RTV, on which there are primary stimuli with value of 50% RTV. The visual experiment was performed by using simultaneous binocular harmonization technique, and it involved 20 respondents. The respondents were tasked with harmonizing the primary stimuli from the test reproduction in relation to the referential one, so that they were to be perceived as equal on both reproductions. For statistical data processing, one-way repeated measurements ANOVA was used, which found statistically consequential differences among means of deviations in perceived lightness of primary stimuli. Post-hoc analysis by Fisher shows pairs that are reciprocally different (p < 0,05). The obtained results clearly indicate the regularities of the appearance of simultaneous contrast effect on printed medium, all with the aim of creating a model for predicting it and finding a conceptual design solution in which the effect is pronounced the least.

The paper presents the results of the research on the manifestation of the chromatic effect crispening, where the primary stimuli are designed as squares in the blue-green color with the values of 55% RTV and 65% RTV, while the secondary stimuli are designed as backgrounds in the purple color and their variations are made in the values of 25% RTV, 50 % RTV, 75% RTV and 100% RTV that surrounds the primary stimuli. Ten respondents of both sexes participated in the research. They had the task to match on a computer screen through the binocular harmonization technique the test primary stimuli with the referential stimuli, so that the test primary stimuli are perceived the same or equal to the referential primary stimuli. The intensity of the effect was determined and presented in the CIEDE00 system. The results of the research show that the intensity of the effect was more pronounced on the test primary stimuli of 65% RTV, where the deviations in the perception of color were more pronounced. The smallest deviation was measured on the primary stimulus of 55% RTV with the background of 75% RTV, which is also a recommendation to the designers when creating a conceptual solution with the combination of pairs presented in this paper.

This research presents the results of the appearance of chromatic effect of crispening on a designer solution in which the primary stimuli are made in the purple color with the values of 55% RTV and 65% RTV and backgrounds are made in the green-blue color, and their variations are designed in the values of 25% RTV, 50% RTV, 75% RTV and 100% RTV that are placed around the primary stimuli. The test subjects (n=10) that took part in the research had the task to equalize the test primary stimuli with the referential stimuli on a computer screen with the help of the technique of simultaneous binocular harmonization. The strength of the crispening effect was defined and shown in the CIEDE00 system. The conclusion of the conducted tests indicates that the intensity of crispening was stronger on the test primary stimuli 65% RTV, where the differences in the perception of color were more significant.