Braille Braille is a system of SIGNS that can be read by touch using the hand. Braille SIGNS consist of one to six raised dots in a 2x3 matrix. That gives the system 63 possible SIGNS. Braille is not scaled up and down. There is no international standard concerning the size of the dots or their internal distance. In the United States, the following dimensions are specified by
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law: dot diameter: 0.059 inches, inter-dot spacing: 0.090 inches, horizontal separation between cells: 0.241 inches, vertical separation between cells: 0.395 inches. Braille is used in two different ways: Grade 1 Braille. Each letter in the alphabet is represented by one SIGN. The SIGNS that stand for letters a to j also serve as numbers one to ten, but are preceded by a special SIGN (dots 3, 4, 5, 6). Grade 2 Braille. Each SIGN stands for a common expression. As a rule, simple words are spelled with Grade 1, while longer messages are written with Grade 2. For use on signs only Grade 1 is recommended.
a/1 b/2 c/3 d/4 e/5 f/6 g/7 h/8 i/9 j/0 k l m n opqrstu vwxyz 198
One problem with Braille is that few people use it effectively. Denmark, for example, has roughly 1,000 fluent Braille users in a population of 5 million persons. Learning Braille implies both discerning between different SIGNS and knowing their meaning. Another problem is that Braille cannot advertise itself at a distance. It has low target value. Braille signboards often come with a semi-circular locator, which helps users to feel the exact position of the SIGNS when the signboard is already found. Braille should be used in places where blind people who read Braille expect to find it, and when possible, they should be informed where to feel for it. Further, Braille messages must be situated in certain positions, heights, and angles that allow users to touch and read them upside up with the hand in the correct position. Users in wheelchairs must also be considered.
Figure 197 Braille locator height 6 mm, width 3 mm, dept 1.5 mm. Figure 198 Braille with Danish measures.
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