65th IFLA Council and General
Bangkok, Thailand, August 20 - August 28, 1999
Presentation of Tactile Materials: The Need for Research
Chief Scientist, Royal National Institute for the Blind,
224 Great Portland Street
London W1N 6AA
Although braille has been the dominant embossed language for blind people for many years, readership is less than 300 per million population in most developed countries. Early this century there were a number of other embossed languages, mainly in the USA, but Moon is the only one still used for book production. Moon was developed by Dr William Moon in England in 1847 and is based on embossed versions of capital letters.
Fig. 1 The Moon Code
Moon is easier to learn than braille, requires less tactual sensitivity and can be used as an intermediary step to learning braille. However Moon is much slower to read than braille and takes up about four times the volume. Moon readership is about 400 regular readers in the whole world.
From time to time other embossed languages appear but their use has been mainly restricted to applications such as labelling; none of them have been adopted on a wide scale although the Fishbourne code has survived for a number of years.
So the question is whether there is a significant unmet need for embossed languages other than braille. It has been suggested that the main potential user groups are:
- Less able visually handicapped children who have not been able to master braille (including large cell uncontracted braille).
- People with a poor sense of touch such as those with diabetic retinopathy.
- People who are deafblind but do not read braille.
- Older people who may only require a system for labelling or reading in limited quantities (eg an instruction booklet).
In countries such as the UK, about 4000 per million of the population have insufficient vision to read visually, but only 300 per million read braille. Therefore there are a very large number of people who have to rely solely on auditory information which has significant limitations (eg with handling numeric information). However most of this population is over retirement age and many of them do not want the effort of learning an embossed language.
It would be unwise to assume that an embossed language suitable for less able children would be optimum for blind diabetics or for an elderly person to read instructions for their medication.
Before deciding whether to develop one or more new embossed languages it is important to assess:
- Demographic trends and their likely effect on the number and type of potential users.
- The unmet needs and how these will be affected by technological developments.
- The infrastructure required such as training services.
- How new technology can be harnessed to simplify production.
- The total cost to develop and establish a new embossed language.
In addition to embossed languages there is also an unmet need for methods of accessing graphical representations. These vary from conventional maps and diagrams to time varying graphics such as on a computer screen. Despite a dramatic increase in the use of graphical representations by the sighted population, this has not been reflected in the use of embossed graphics by blind persons.
For small quantity production, as for educational material for visually disabled children, the technology exists to economically produce large print texts in a format to suit an individual. For instance, with modern word processors it is relatively simple to produce versions of the same text with different type sizes, typefaces and line spacing. It becomes somewhat more complex to automate the production of graphics to suit individual needs, but computer-assisted methods can greatly reduce the time compared to traditional methods.
However there is a need to develop equivalent systems to facilitate the production of embossed materials to suit an individual. Some of the technology exists, but there is a lack of research on how to determine what is the optimum presentation for an individual; this is particularly noticeable in the area of embossed graphics.
Customisation of a visual presentation can also be done with time variant displays. With a public access terminal, the user's card could store information about their preferred mode of interaction. For instance a user might like large characters on the screen of a cash dispenser or more time to dial on a public telephone.
However there are other areas where it is not practically possible to tailor the display to the individual. For instance subtitling on television has to be generated before transmission and there is limited scope for having the presentation under user control. In this type of application it is important that the presentation is designed to be usable by as large number of potential users as possible. In the UK the introduction of digital television gave the possibility of designing the font for subtitling to suit, as far as is possible, people with low vision. The philosophy was that a typeface good for people with low vision would be good for everyone. Therefore ScreenFont was developed and is now in use for subtitling digital television programmes in the UK.
Fig 2 An example of ScreenFont.
This approach has been so successful that variants of the font are being developed for computer use, fixed signage and printed instructions for public terminals. These are all areas where the legibility of the typeface is more important than the aesthetics or reading speed; such an approach would not be suitable for developing a typeface for large print books.
Technological developments are making it simpler to produce material in the presentation preferred by an individual user, but research is needed to identify the optimum presentation for a particular potential user.
Gill J M The Use of Digitally-Stored Text for Braille Production. National Computer Conference, New York, June 1976. Reprinted in Braille Automation Newsletter, Aug 1976, pp 6-10; and in Sigcaph Newsletter, ACM, No 20, July 1976, pp 21-24.
Gill J M New Moon. British Journal of Visual Impairment, Vol 3, No 3, 1985, pp 85-86.
Gill J M The Integrated Production of Braille, Moon and Large Print. Proceedings of Fifth International Workshop on Computerised Braille Production, Winterthur, Switzerland, 1985, pp 123-125.
Gill J M Alternative Written Media for the Visually Disabled. Proceedings of the EEC Workshop on Production of Hardcopy Materials for the Blind, Toulouse, France, Oct 1986, pp 157-159.
Gill J M Determining Priorities for Future Technological Research for Visually Disabled People. Conference of Association for Education and Rehabilitation of the Blind and Visually Impaired, Kitchener, Canada, July 1993.
Gill J M, Silver J H & Wolffsohn J S W Smart Cards and User Selectable Interfaces. Proceedings of the COST 219 Seminar on Smart Cards and Disability, ISBN 1 86048 003 9, Nov 1994, pp 68-78. Also at http://www.stakes.fi/cost219/smartc94.doc
Gill J M Access Prohibited? Information for Designers of Public Access Terminals. ISBN 1 86048 014 4, May 1997, revised March 1998. Also at http://www.eyecue.co.uk/pats
Gill J M, Silver J, Sharville C, Slater J & Martin M Design of a Typeface for Digital Television. Third Tide Congress, Helsinki, June 1998. In Placencia Porrero I & Ballabio E Improving the Quality of Life for the European Citizen. IOS Press, ISBN 90 5199 406 0, 1998, pp 248-252. Also at http://www.stakes.fi/tidecong/632gill.html