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Tactile versus braille

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tactile should be a separate media type than braille


This wiki page is partial fulfilment of HTML Accessibility Task Force ACTION-7, entitled: "propose braille media type (as opposed to simply tactile) or sub-type after consulting with Braille-in-DAISY and others"

This wiki page will enable me to point pertinent experts to a common starting point; The issues enumerated below need more investigation and discussion before they are broached with the CSS working group/Style Activity.

Definition of Terms/Analysis

The term "tactile" covers items such as thermoformed objects, for example, maps; raised line illustrations and other tactile information that requires no prior knowledge in order to be successfully interpreted by an individual. This term connotes tactile illustrations and charts, not a representation of natural language.

The term "braille", on the other hand, specifically refers to a representation of a specific natural language. In order to understand braille, prior knowledge of the national version of braille being rendered (or into which the text is being translated in accordance with user settings and preferences) is necessary.


"braille" is a fundamentally different category from "tactile". However, although it is a representation of a natural language, "braille" is not equivalent to "text", as it is classified by CSS as belonging to the "grid" media group; one might, for example, provide a stylesheet to enable a user to "Emboss This", much as sighted users are served an @print stylesheet when a "Print This" link is actvated.

What is needed, therefore, is a supplemental CSS media type which would belong to the "continuous or paged" media group and which could be classified as either interactive (refreshable braille) and static (embossed/final form braille).

A potential obstacle is that the term "tactile" is currently used by CSS to catagorize media groups by sensory type: "visual/audio/speech/tactile"

There is, however, precedent in that "audio" and "speech" are treated as discrete concepts, so too should "braille" and "tactile" be treated as the separate concepts they are. There is great room for flexibility in this realm, as braille stylesheets are -- for the most part, if not entirely -- theoretical constructs, despite the Braille Stylesheets Preliminary Requirements Analysis. Thus, the amended list of media types would be: : "visual/audio/speech/tactile/braille"

For Reference

CSS 2.1 defines the following media groups:

  • continuous or paged.
  • visual, <code>audio, speech, or tactile.
  • grid (for character grid devices), or bitmap.
  • interactive (for devices that allow user interaction), or static (for those that do not).
  • all (includes all media types)

CSS 2.1 defines the following media types:

  • braille
  • embossed
  • handheld
  • print
  • projection
  • screen
  • speech
  • tty
  • tv

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