These specifications define the size of braille dots and the distance between them on signage as recommended by the Australian Braille Authority.
While these standards allow for a range of dimensions, there should always be internal consistency on a sign with a maximum of 1% variation.
A braille character is composed of a combination of dots from a matrix of three rows and two columns, known as a cell.
Distance between dots
Horizontal or vertical distance from centre to centre of adjacent dots in the same cell = 2.3 mm – 2.5 mm
Horizontal distance from centre to centre of corresponding dots in adjacent cells = 6.0 mm – 7.0 mm
Vertical line spacing from centre to centre of nearest corresponding dots in adjacent lines = 10.0 mm – 11.0 mm
A gap between words is indicated by a blank braille cell.
Dot size
dot base diameter = 1.5 mm – 1.6 mm
dot height = 0.6 mm – 0.9 mm
spherical radius = 0.76 mm – 0.81 mm
Spherical radius r is related to the dot base diameter d and dot height h, as illustrated in the diagram below.
The Australian Braille Authority is a subcommittee of the Round Table on Information Access for People with a Print Disability Inc.
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