## 4 Discussion  
The primary goal of this research was to explore the effects of different color combinations and medium types on participants' cognitive outcomes. We compared achromatic (black on gray), achromatic-chromatic (black on green), and chromatic (purple on green) color pairs across digital and print mediums, measuring their impact on reading time and participants' comprehension score. Variations in our color combinations were found to affect text legibility, which supports our first hypothesis H1. The analysis revealed a significant difference in one color combination compared to the other two. Specifically, the participants took less time to read black text on green background than the same text on gray background. The reading time was shorter compared to the purple text on green background as well. These findings indicate that a combination of achromatic and chromatic colors may be a more effective choice, at least when the goal is to reduce reading time. This conclusion applies specifically to the color hues examined in this study. In the context of product promotion, reduced reading time may create the possibility for additional time to view the product itself or to read other information which would be relevant for making an informed and thoughtful purchase decision. Previous studies have also demonstrated the effectiveness of the achromatic-chromatic combination. [PERSON] at al. [18] noted that color combinations with black text were more effective than those with white text when paired with other background colors. [PERSON] et al. [15] aimed to determine which color composition first captures users' attention. The results indicated that white attracted sustained attention more strongly than other colors, regardless of the background color, while yellow and black could also be considered effective for this purpose. [PERSON] et al. [10] observed that red text on a white or light grey background provided the fastest reading speed. According to [PERSON] et al., the highest legibility among dark text on light background combinations was achieved with black or blue text [2]. In their study, [PERSON] et al. [36] examined the effects of color combinations on legibility and aesthetic perception within popular negative polarity interface designs. Interestingly, the results indicated that background color did not have a significant effect, while higher brightness contrast led to increased legibility. In the context of contrast calculations between the text and background in our study, the CIEDE2000 values for the selected combinations showed a significant contrast, indicating excellent visibility. Specifically, the AC combination with a value of 33.67 indicated a strong contrast, ensuring good discriminability even for users with impaired vision. It appears that an optimal level of contrast positively impacted the reading performance among our participants. Our results show that there was no difference in reading time between achromatic (black on gray) and chromatic (purple on green) color combination. This may indicate that promotional texts with monochromatic or overly vivid designs might not be ideal for  
Figure 4: Comprehension score across conditions. enhanced legibility. While it was not found to be the optimal choice for text color combinations in our study, it is worth noting that its use may be desirable in other applications. Although complementary colors are vibrant, their balance creates natural harmony. This balance attracts the eye and conveys a sense of completeness, which can enhance the overall impression of a brand or product [37]. It is important to consider that color perception is not only determined by lightness, chroma, and hue but also by the distance and angle from which the color is viewed, the type and intensity of surrounding light, as well as the occurrence of other colors in the surrounding context and broader environment [38; 39; 40]. Unlike the effect of color hue combination, the medium had no impact on the participants' performances.