## 3 Results and Discussion
### Legibility of Prints  
Figure 4 shows the influence of type size on reading time. There was a significant effect of type size on reading time F(1.74, 85.36) = 64.03, \(p\) < 0.001. Post hoc analyses with Bonferroni adjustment indicated that the texts in 12 pt were read faster (_M_ = 27.82 s, _SD_ = 4.23) than the texts in 10 pt (_M_ = 28.38 s, _SD_ = 5.44), t(199) = 2.78, \(p\) < 0.05 and the texts in 8 pt (_M_ = 31.69 s, _SD_ = 4.88), t(199) = 9.52, \(p\) < 0.001. The texts in 10 pt had a shorter reading time than the texts in 8 pt t(199) = 7.38, \(p\) < 0.001. From the results, it can be inferred that in longer texts and higher type sizes, such as size 12 pt, the contrast between the background and the text significantly contributes to faster reading or better legibility. Commercial office paper (S1) has the highest whiteness. At smaller sizes, contrast is crucial for the reader's ability to recognise individual characters. At larger sizes, where challenges in character recognition are not significant to the same extent, the combination of type size with a pronounced contrast enhances reading speed, i.e., legibility. Similar results, i.e., that a higher type size reduces reading time, were found in previous research [34; 35], especially if the contrast between the background and printed text was reduced. Prior works suggest that contrast plays an important role in visual communication in terms of supporting functional legibility [55] and that poor contrast is one of the main factors that can cause difficulty for readers in general [56]. Figure 5 shows the influence of paper type on reading time. There was a significant effect of paper type on the participants' reading time F(1.48, 72.49) = 5.74, \(p\) < 0.05. Additional post hoc analyses with Bonferroni adjustment indicated that the texts printed on Japanese knotweed paper (S2) (_M_ = 31.69 s, _SD_ = 4.89) had a shorter reading time than the texts printed on giant goldenrod paper (S3) (_M_ = 34.03 s, _SD_ = 7.92), t(149) = -3.31, \(p\) < 0.005. Similarly, the texts printed on commercial office paper (S1) (_M_ = 31.26 s, _SD_ = 5.34) had a significantly shorter reading time than the texts printed on giant goldenrod paper (S3), t(149) = 6.98, \(p\) < 0.001. The texts printed on commercial office paper (S1) also had a shorter reading time than the text printed on black locust paper (S4) (_M_ = 32.34 s, _SD_ = 6.00), t(149) = 3.04, \(p\) < 0.005. The other comparisons were not statistically significant. The shortest reading time was measured on commercial office paper (S1). These findings demonstrate  
Figure 3: Samples of 8 pt and 10 pt Arial typeface printed on commercial office paper (S1), Japanese knotweed paper (S2), giant goldenrod paper (S3), and black locust paper (S4). that legibility is influenced by the whiteness of the background surface. While commercial office paper (S1) offers the most optimal conditions for a high text-background contrast, such high contrast levels were not achieved on the different IAPS papers. Among the papers from the IAPS, the reading time was the shortest for the texts printed on Japanese knotweed paper (S2) and the longest for the texts printed on giant goldenrod paper (S3). The latter finding is in accordance with our expectations, as we can see that, in line with the papers' properties (Table 1), whiteness with UV of the IAPS papers (S2-S4) is just about one third of the value for commercial office paper (S1). This is especially important when the typeface has at most a moderate x-height [43]. Figure 4: Average reading time for texts in different type sizes (8 pt, 10 pt, and 12 pt) printed on commercial office paper (S1), Japanese knotweed paper (S2), giant goldenrod paper (S3), and black locust paper (S4). Figure 5: Average reading time for texts printed on commercial office paper (S1), Japanese knotweed paper (S2), giant goldenrod paper (S3), and black locust paper (S4). The Cochran Q test was performed to analyse the effects of paper type and type size on the correctness of participants' answers (Figure 6).