In the achromatic White's grid, the grey patches between the grey lines are perceived as darker while the same elements inserted between white lines are perceived lighter than their true measured values. A number of authors attempted to calculate the magnitude and direction of this effect using mathematical models based on multiple spatial filters. This paper uses different mathematical model, based on regression analysis, which has shown itself as an excellent tool for prediction of direction and magnitude of White's effect. The psychophysical visual experiment was conducted on 38 subjects of both genders. The differences in lightness perception ∆L00 were calculated in CIE ∆E_2000 system. This paper determined the functional dependence of White's effect magnitude ∆L00 to the lightness L of rectangular elements in White's achromatic grid. The results gave the square polynomial of very high quality (R2 = 0,974). Regression polynomials were also found. The gave numerical values ∆L00 of difference in perception of left and right elements in comparison to their physical values (left R2 = 0,943, right R2 = 0,938) in dependence to variation of lightness parameter L. Results of the research clearly show the mathematical pattern of White's effect based on the lightness of rectangular elements.

Attracting and retaining the attention of users, or motivating them to use the particular product being the main task of designers in graphic design for all materials, from printed to digital media. It is crucial to select colors that are more appealing to the target audience. The aim of this paper is to explore the differences in color preferences depending on age groups in a nationally representative sample of the Republic of Croatia consisting of 1,000 research participants. For this purpose, a questionnaire was created to collect information on the color preferences of participants, and as a result of this research, it was determined that there are statistically significant differences in the preferences for certain colors depending on the age groups of the participants. It has also been shown that there are both increasing and stable or decreasing trends in color preferences depending on age groups.