1.3 L2 SC1: Any information that is conveyed through color is visually evident without having to interpret color. For example, the distinction can additionally be determined through context, characters, or symbols that accompany the color presentation, or through pattern differences such as dotted red vs. solid green lines in a graph.

Tactile graphics

This technique relates to the following sections of the guidelines:


Make image structure available to the sense of touch

Visual images may be converted into tactile form. For example, images can be printed as detailed reliefs using a specialized adaptation of Braille. Alternatively, the images can be printed on special paper and converted into raised-line drawings (as in the example from the Tate Gallery's IMAP project discussed in the technique on using alternative views to show the structure of complex images). These relief drawings can also be used as overlays on a digitizing tablet. With the aid of additional software, the image becomes a "touch screen" and provide spoken output as the user presses different areas.

  • The University of North Carolina's BATS project produces maps that use both tactile and auditory cues to provide information about locations and the distances between them. See Mark Tosczak "A New Way to Read, Not See, Maps." Wired News September 25, 2002. Available at http://www.wired.com/news/school/0,1383,54916,00.html. Accessed August 26, 2004.

  • Liddy Nevile's "Accessible Diagrams" page (2002) provides a useful overview of techniques and technologies for producing tactile graphics, both on- and off-line. Available at http://www.latrobe.edu.au/webaccess/diagrams.html.