When Light Is Too Light: Font Weight in Arabic for Global Interface Design

Nilsu Atilgan^1,2 (), Ben D. Sawyer²; ¹Bilkent University, ²University of Central Florida

Digital reading depends on typographic choices that support efficient and comfortable perception, yet empirical guidance for non-Latin scripts remains limited. Arabic, one of the most widely used writing systems, differs fundamentally from Latin in its connected letterforms, spatial density, and visual structure, meaning that weight ranges optimized for Latin text may not generalize to Arabic. We examined how font weight affects both functional readability and subjective experience in Arabic. Thirty-two native Arabic speakers (mean age 35.0 years) read narrative passages in Noto Sans Arabic at three weights: Light (100), Medium (400), and Bold (900). Participants read nine passages in total, with reading speed (words per minute) and comprehension measured, followed by ratings of comfort and preference. Reading speed varied systematically with weight. Medium (400) produced the fastest reading (191 WPM), followed by Bold (181 WPM) and Light (170 WPM). The difference between light and medium weights in reading speed reached near significance, with a 21-WPM (p = 0.09). Comprehension did not differ across weights. Subjective judgments closely matched performance: Medium was the most preferred and comfortable, while Light was consistently rated least comfortable and least preferred. Bold was often rated as comfortable, suggesting that well-designed Arabic typefaces can support heavier weights without a perceptual cost. These results indicate that ultra-light Arabic fonts impose a measurable functional penalty. As peripheral vision is sensitive to spatial frequency, the thin strokes and high white-space ratio of light Arabic fonts may reduce peripheral preview. In addition, light weights have high perimetric complexity but low ink density, which can obscure the perceptual “skeleton” of complex Arabic letterforms needed for rapid word recognition. Together, these findings show that optimal weight ranges are script-dependent and motivate vision-science-based, multiscript-aware typographic design guidelines.