Understanding the influence of paper surface structures on color perception is crucial for the printing industry. This research investigates the impact of horizontal and vertical parallel lines on chromatic assimilation using the Munker-White grid model. The study employs the perceived ∆E00 metric to quantify color differences and determine whether these textures affect perceived color accuracy and consistency differently. Results reveal variations in color perception due to surface textures. The biggest color difference (ΔE00) occurred at 60% RTV coverage for cyan, where the vertical structure showed a significantly lower value than the horizontal. For the yellow primary stimulus, the greatest difference was observed at 20% RTV coverage, with both structures showing high initial values that decrease with increased coverage. These findings provide valuable insights for improving color management practices and enhancing the quality and reliability of color reproduction on various substrates, contributing to advancements in printing technology and color science.

Various parameters and observation conditions contribute to the emergence of color. This phenomenon poses a challenge in modern visual communication systems, which are continuously being enhanced through new insights gained from research into specific psychophysical effects. One such effect is the psychophysical phenomenon of simultaneous contrast. Nearly 90 years ago, Kurt Koffka described one of the earliest illusions related to simultaneous contrast. This study examined the perception of gray tone variations in the Koffka ring against different background color combinations (red, blue, green) displayed on a computer screen. The intensity of the effect was measured using lightness difference ΔL₀₀ across light-, medium-, and dark-gray tones. The results were analyzed using descriptive statistics, while statistically significant differences were determined using the Friedman ANOVA and post hoc Wilcox tests. The strongest visual effect was observed the for dark-gray tones of the Koffka ring on blue/green and red/green backgrounds, indicating that perceptual organization and spatial parameters influence the illusion’s magnitude. The findings suggest important implications for digital media design, where understanding these effects can help avoid unintended color tone distortions caused by simultaneous contrast.

Flexo printing or flexography is the most common letterpress printing technique today. Compared to other printing techniques, the advantages of flexographic printing are higher printing speed, low material losses, the possibility of using water-based...

Gamification is widely used to enhance student engagement in higher education, yet its effects in English for Specific Purposes (ESP) contexts, particularly from a Self-Determination Theory perspective, remain underexplored. This study examines whether gamification in a Moodle-based ESP course is associated with differences in students’ course satisfaction. A total of 94 undergraduate students participated in a quasi-experimental study, enrolling in either a gamified or non-gamified course format. Gamification was implemented using the Level Up plugin and H5P interactive activities. Students’ perceptions were measured using selected items from the Course Satisfaction Questionnaire. Non-parametric analyses (Mann–Whitney U tests with Holm–Bonferroni correction) were applied. Results show statistically significant differences favoring the gamified format in engagement and enjoyment, motivation to participate, and willingness to recommend the course. Differences in perceived competence and support for individual learning were positive but not statistically significant. These findings suggest that gamification in ESP is associated with more favorable motivational and affective dimensions of course satisfaction, while effects on broader learning-related perceptions remain less conclusive. This study contributes by providing evidence from a controlled LMS-based implementation and highlights the importance of theoretically grounded gamification design.

This paper examines how different background color combinations influence the perception of grey tones in primary stimuli within modified Koffka ring configurations displayed on a computer screen. A custom software application was used with 60 observers, who adjusted perceived grey tones for three primary lightness levels (dark, medium, light) across 27 test samples combining three Koffka ring variants and chromatic backgrounds (red, blue, green). The strength of the simultaneous contrast effect was quantified using the color appearance difference ΔE₀₀, while accompanying shifts in chroma (ΔC) and hue (ΔH) were also evaluated and analyzed by descriptive statistics, Friedman ANOVA, and post hoc Wilcoxon signed-rank tests. The results show that the effect is strongest for dark-grey tones and clearly visible on blue–green and red–green backgrounds, moderate on red–blue backgrounds, and weak or negligible for light-grey tones, with ΔC and ΔH remaining very small, indicating a predominantly lightness-based illusion. These findings provide guidance for digital media design by indicating which combinations of grey levels, spatial configurations, and background colors are most likely to produce unwanted simultaneous contrast in screen-based applications.