PART 3 | Typography for the Blind
The new ADAAG is significantly more stringent in the area of typography for the blind. Reading tactile letters is extremely difficult. The letters must be relatively consistent in size and shape on every sign in the environment in order to be easily read. Tactile letters must also be smaller in size and simpler than most visual letters in the environment. Tactile type, though, applies only to permanent room identification signs; these apply to rooms that will not change names for at least a year.
Height of Tactile Letters
There is only a narrow band of allowable heights for tactile letters: 5/8" minimum and 2" maximum based on the letter "I" (703.2.5); _" minimum letters are allowed on dual signs. Tactile letters must always be capitalized. Tactile letters must also be minimum 1/32" in height from the surface of the sign. They may be beveled or chamfered.
Character Proportion and Stroke Width
Tactile letters must be san serif and always capitalized. Characters must be selected from fonts where the width of the uppercase letter "O" is 55 percent minimum and 110 percent maximum of the height of the uppercase letter "I" at the top of the tactile text (703.5.4). The stroke width may be only 15% maximum of the height of the letter "I" (703.5.6). This rule makes most san serif fonts not permissible for use, including Times Roman, bold fonts, and Optima. Stroke width rules are only for the top of tactile letters. If bold characters are beveled, they may comply.
Click here to read the rest of SEGD ADA White Paper Update 2 2006 PDF
