Influence of distance between dot pattern and braille in tactile graphics by emboss printing method on the ease of braille identification

Tactile graphics containing only dots have long been widely used. However, tactile graphics containing only dots may be mistaken for braille. This study aimed to investigate the influence of distance between dot pattern and braille in tactile graphics by emboss printing method on the ease of braille identification. Test pieces with varied distance between dot pattern and braille in tactile graphics were created using EDEL software, which is a de facto standard in Japan, and printed using the ESA721 braille printer (JTR Co.). Sighted subjects who were beginner braille readers and subjects with visual impairment who were expert braille readers were asked to identify the test pieces. The results showed that the visually impaired who regularly use tactile charts and braille could identify braille accurately, quickly, and with confidence when the vertical and horizontal distance were 4.7 mm or greater. For novice braille readers, they were able to identify braille accurately, quickly, and confidently when the vertical distance was 5.9 mm or greater and the horizontal distance was 4.7 mm or greater. These results indicate that the novice readers can identify braille correctly, quickly, and confidently when the vertical distance is 5.9 mm or greater and the horizontal distance is 4.7 mm or greater. In addition, test pieces with extended vertical distances were easier to identify than those with extended horizontal distances.