Tactile formats use raised or embossed symbols in place of printed characters. These can be 'read' by visually impaired people.
Braille is a system of writing where letters and numbers are represented by combinations of up to six raised dots arranged in two columns for each character - known as a cell. The original form of Braille is now known as Grade 1; in this all words are spelled out. In Grades 2 and 3, there are contractions (for example a single character for 'ing' or 'ed'), which make reading faster. It is important for a user to know the grade of Braille; someone who only knows Grade 1 will not be able to read all the text in a Grade 2 version.
In addition to literary Braille for text, there is also Nemeth Braille for mathematics, and a form of Braille for science.
Because Braille characters take more space than print, a single volume original work will become several Braille volumes. Knowing the number of volumes enables users to estimate the length of the text.
Braille is produced in various layouts. Single sided has braille embossing on one side of a page only, while double sided has braille on both sides. Spacing between lines of braille also varies, being either single spaced or double spaced. In Jumbo braille, the cells are larger giving more space between the component dots; some people find this helpful when learning braille.
Moon is another form of tactile writing. It uses raised letters of the alphabet in a simplified form. Like Braille, there are different grades of Moon and users need to know the grade level of a text. People who lose their sight later in life often find Moon easier to learn than Braille.
Maps and diagrams are converted to tactile representations in a variety of ways. One method is to use collage technique, where shapes are cut out of card and mounted onto a backing mount. Shapes may be given a textured surface to help distinguish different parts; for location maps in public places, the mount and shapes may be made of wood or plastic. Another method is to print the map or diagram onto heat sensitive paper; when heated the printed shapes and lines become raised; sometimes referred to as 'swellpaper' or 'thermoform'. Maps and diagrams may have labels on them in a tactile text (e.g. Braille) or have accompanying audio descriptions.
There is a specific form of Braille for musical notation. The notation may be laid out in a variety of ways - bar-over-bar, phrase-by-phrase, etc. Regular users of Braille music will usually prefer a specific layout.