Tactile Graphics: An Overview And Resource Guide

INTRODUCTION

This article is intended primarily for parents, teachers, and friends of blind people. It introduces the reader to some of the possibilities and to some limitations of using tactile graphics for conveying information to blind people. A number of methods for producing tactile graphics are described. A resource list of useful tools, supplies, and technological methods and devices, and the names and addresses of firms and organizations selling these products is included. A major focus of this article is tactile graphics in science, engineering, and math.

Tactile graphic images are used by blind people to obtain information that sighted people get from looking at pictures. Students learning geography for example would be lost without maps of regions being studied. A blind student without equivalent tactile maps is at an enormous disadvantage relative to sighted peers.

PREPARATION OF TACTILE GRAPHIC MATERIALS

Professionals working in organizations serving blind people routinely make topographic maps, images of animals, and other quasi-three-dimensional pictures for their clients. Most are made by thermoforming a plastic sheet over a hand-made mold. The mold can be anything that is porous and can withstand the temperature of the thermoforming process. Many molds are made by cutting and pasting paper, cardboard, string, metal foil, etc onto a heavy paper base. Heavy acrylic paint (e.g., Liquitex brand) can be squirted through a syringe to make into intricate patterns of raised lines. The paint dries in about an hour.

Some of the things used to make the molds are common materials in the home. Most are common supplies available in arts and crafts shops. The syringe used by many professionals is a "onojector" available from drugstores, pet stores, or veterinarians.

Braille wording can be added to these tactile pictures using a braille slate and stylus---available from almost all firms and organizations selling general supplies for blind people.

Another technique for making molds is by deforming soft aluminum sheets with various tools. The American Printing House for the Blind has a kit that includes a number of these aluminum sheets and a selection of useful tools and dies for making images on the sheets. The kit includes a punch and die set for putting braille wording on the mold.

The American Printing House also sells a Starter Graphics kit intended primarily for non-professional production of single copy tactile graphic pictures. This starter kit includes fabric puff paint and a squeeze bottle applicator, a number of different fabrics with different textures, several sheets of glue-on tactile labels, a braille slate and stylus, and a guide to braille. One can also use the starter kit to make molds from which thermoform copies can be made, but users caution that the puff paint mold should be powdered with talcum to prevent the puff paint from sticking to the plastic thermoform sheets if used for this purpose.

Many volunteer and professional transcribers working for public and private organizations providing materials for the blind use these methods routinely to make excellent quality maps, relief drawings, etc. Prof. Judith Tamburlin and Prof. Charles Severin of the State University of New York at Buffalo [1] have established a research program to develop high-relief educational materials used in the life sciences. Their largest project to date is a three volume atlas of human anatomy with over 100 illustrations. It is used in the university and by high school students. They distributed three copies of the atlas to each state resource center or agency designated for the dissemination of educational materials to visually impaired students and their teachers.

At the present time, virtually every variable height tactile picture or the mold from which it is made is constructed by human hands. High-tech production methods are topics of research, but none are presently being employed for any large scale production. There are at least three research projects underway in the US employing computer-controlled milling machines to make molds [2-4] and one using a new stereolithographic instrument [4] for making molds. These research projects show promise for simplifying the process and reducing the human labor required to make variable-height tactile pictures, but the cost of the machines is large enough that they are unlikely to replace the human cut-and-paste process any time in the very near future.

Thermoforming requires a Thermoform Duplicator---a heated press that takes the mold and a piece of Braillon sheet. When the press is closed a partial vacuum pulls the heated Braillon sheet around the mold making a faithful copy of the original. Several standard sizes can be made using supplies and equipment available from American thermoform. Several different weight Braillon is available. The lighter weight is satisfactory for regular size braille pages, but heavier weights are generally recommended for large sizes.

UNIFORM HEIGHT (2D) PICTURES

Variable height tactile pictures are very useful for conveying three-dimensional shape information such as topography and the shapes of various objects. Uniform height tactile pictures are the tactile equivalent of visual line drawings and convey only two dimensional information. For simplicity these will be called 2D tactile pictures from now on.

Manual methods of making 2D tactile pictures

Any of the methods used for variable-height tactile pictures can also be used to make 2D tactile pictures, but there are several methods useful for 2D pictures that are faster and easier than the laborious methods described above.

A popular and inexpensive raised line drawing pad, sometimes called a Sewell pad, provides a "quick and dirty" method of making 2D tactile pictures. One places thin sheets of a special mylar polyester film on the rubberized pad and sketches pictures using some kind of stylus with a rounded tip. Many sighted people find it convenient to use a ball-point pen as stylus, because the pen leaves a more visible image. The sketched lines pop up, and a permanent image is obtained. The height of the image is marginal, but this pad can be a very useful means of instant graphic communication with blind people. A kit consisting of the rubberized pad, a stylus, and a number of mylar sheets is available from most organizations selling general supplies for blind people and costs typically $25 to $30. 8.5 x 11 inch mylar sheets cost $8 to $10 for a package of 100.

Instant tactile images may also be created with the use of a special paper that swells when heated. One can draw directly on swell paper using the Thermo Pen (from Repro-Tronics and its dealers). One must draw slowly and evenly with the Thermo Pen to obtain good quality tactile images, but with practice and some care, one can create good quality images. The Thermo Pen and swell paper is a somewhat lower and more expensive alternative to the raised line drawing pad for instant graphic communication, but the resulting images can be much more readable than the mylar raised line drawings made using the drawing pad. Swell paper is manufactured by Matsumoto Kosan (whose US representative is JP Trading) and Repro-Tronics.

Another way of using swell paper is simply to draw an image using a black felt-tip pen, grease pencil, etc. onto the swell paper surface. The paper is then fed into a machine that passes it under a heat lamp. When the machine is properly adjusted, the black areas of the paper swell but the white areas do not. With some practice, one can make excellent tactile images.

A picture may also be copied onto swell paper using a photocopier and then passed through the swell paper machine. A fast photocopier usually does a better job than a slow one. Slow photocopiers sometimes heat the swell paper enough to cause the white areas to swell slightly and become somewhat textured.

The least expensive swell paper machine available in the US is the Thermal Image Enhancer manufactured by Repro-Tronics. The Stereocopier machine, available from JP Trading, combines the copying and swelling machines into one. With this machine, a picture can be copied directly to a tactile representation.

A common method employed by many professionals to emboss excellent quality images into braille paper is by using A small hand-held tracing wheel. The tool is used to press a line or other image into paper mounted on a firm rubber mat. Since the picture is drawn onto the paper from the back, it must be drawn in mirror image. Howe Press sells these tracing wheels and a variety of other tools for embossing, including a number of tools intended for geometry and math. A Grifhold pounce wheel, available from art supply shops, as well as marking wheels available in fabric shops are also useful for embossing lines.

2D images may be drawn on paper with the acrylic paint or fabric puff paint mentioned above. In addition, a standard hot glue gun can be used for making reasonably good tactile images and has the advantage that it dries much more quickly than the paint.

Bulk production of 2D pictures

A variety of methods are used for producing tactile pictures when large volumes are needed. The thermoforming method described above is one such method. Large printing houses for the blind have presses that squeeze braille paper between heavy metal embossing plates. The male/female embossing plate pairs are made by a human-controlled machine and require a skilled operator to achieve reasonable quality. The total cost of making a pair of embossing plates is many hundreds of dollars. R The Braille Institute has developed a printing press method that utilizes a single embossing plate. Paper is pressed between this embossing plate and a rubber material. The images are not as crisp as those produced by good quality embossing plate pairs but are good enough for most purposes. The single embossing plates can be made from standard photoresistive plates and can be produced for $20 to $30 typically. R Hy-tech Forming Systems has developed a pressure bladder that can be used with single embossing plates to produce excellent quality graphic materials. The company has expressed interest in developing presses for the tactile graphics market. R Most printing houses for the blind are willing to accept outside requests for bulk print jobs, although some may not have the capacity for producing non-standard tactile graphics. A Canadian service company, Braille Jymico, offers to make tactile printouts in large or small quantities using a unique polymer deposition printing method. R A recently-founded company, Tactile Vision [5] Inc, Oakville, Ontario CANADA has developed a new method for inexpensive bulk printing of high-resolution tactile graphics using a deposited polymer. This company can make excellent tactile copies from black and white drawings having lines and dots of order 0.05 inches wide. This is a very promising technology that could become the standard bulk process of the future. R Computers and tactile graphics

Computers are rapidly becoming indispensable tools for blind people. Screen-reader software programs combined with either refreshable computer braille displays or voice synthesizers provide unparalleled access to electronic literature. R Computers are also excellent tools for producing high-quality inexpensive 2D tactile pictures. Many images needed by blind students or professionals are increasingly available as computer files. Software for creating and editing graphics files is relatively inexpensive and user-friendly. A number of computer programs, discussed in the next section, are becoming available specifically for creating tactile images. If there were such a thing as a personal tactile-image printer, the creation of 2D tactile pictures would become essentially a trivial exercise in manipulating and printing graphic computer files. R Computers can also assist enormously in conveying information to blind users about 2D pictures. This topic is discussed extensively in a later section. R Computer hardware for making 2D tactile pictures

For a period of time in the early 1990's, the HowTek Pixelmaster wax jet color printer was available with a modification that permitted a thick layer of the printer's polymer ink to be deposited. The printed images had a height of almost 0.010 inches. Although this height is much lower than the standard braille dot height of 0.025 inches, it was thick enough to be a useful tool for making 2D tactile pictures. Unfortunately the product failed on the commercial market, and at the present time, there is no commercially-available computer printer capable of making a tactile printout of a quality useful to blind people.

Until a usable and affordable tactile computer printer becomes commercially available, the only practical small-scale method by which a computer image may be transformed into a high-resolution 2D tactile picture is by using swell paper. Most computer printers heat the paper too much to allow direct printing on swell paper, so the computer image is normally printed onto regular paper, and the image is transformed into a tactile picture by methods described in the previous section.

Most braille printers may be switched into a mode for printing graphic images in the form of braille dots. Many of them have high resolution modes that print dots on a grid with dot-to-dot spacing of order 0.08 inches or less. Images printed with small dot spacing feel markedly smoother than those with the standard braille dot spacing of 0.1 inch.

Braille graphic images even with small dot-spacing are not as universally useful as high-resolution images made by other methods. Even so, braille graphic resolution can be very effective for many purposes. A few computer programs intended for production of braille graphics, many of which are usable by blind people, are described in the following section.

Computer software for making 2D tactile pictures

Several manufacturers of braille printers sell computer programs that permit a user to print out graphic images. These proprietary programs are not discussed here. The owner or potential purchaser of a braille printer should contact the dealer or manufacturer for information about such programs. KanSys supplies an inexpensive program, LowRez, that can print graphics files from a PC computer to many braille printers.

There are a few programs available that allow a user to print graphs of functions on braille printers. These programs may be used by blind people and are likely to be useful in advanced math and science. One such program is Graph-it sold by Blazie Engineering. This program runs on their popular Braille Lite note-taker and prints to most popular braille printers. They also sell a PC version.

Sighted computer users can design graphics on almost any computer graphics program and can add Braille through the use of Braille Font packages available from Duxbury, Inc. Prof. Marie Knowlton [6], University of Minnesota, has modified a version of the MacPaint program for the Macintosh to include braille fonts and useful tools for making graphics for blind people. Images made with any of these programs may be transferred to swell paper from which tactile pictures are obtained, as described above.

A recently-introduced program called AudioCAD allows both sighted and blind computer users to design images and print them on swell paper or on braille printers. AudioCAD includes several additional features that are described below in a section on including hidden information in computer files.

USING TACTILE GRAPHICS

Few sighted people fully understand the great difference between 2D tactile and 2D visual perception. It is far more difficult for a blind person's fingers and hands to provide him/her with the kind of overview of a tactile picture that sighted people perceive instantly with their eyes. The human eye and its associated parts of the brain can take in and process much more information in a moment than can be perceived by tactilely in hours.

Most people who are born blind or who lose their sight at an early age have great difficulty understanding information presented in 2D tactile pictures. Sighted children have to learn about parallax, representation of 3D objects by 2D projections, and use of spatial position in such things as maps and graphs. Blind children seldom have access to comparable tactile pictures and do not develop these concepts. As a consequence, blind students often have great difficulty with topics such as geometry and function graphs that are typically taught using 2D pictures.

The best advice known to this author on how to use and not use tactile graphics was given by Ms. Cathy Mack, a former special education teacher and expert on technologies for blind children. An excerpt from her contribution to a symposium on tactile graphics [7] follows:

"When you introduce a tactile diagram, whether it's to a kindergartner or to an adult, it's important that it be presented in an informational way, not as a guessing game. Many times I've seen a person hand a tactile diagram to someone and say `can you tell what this is?' You have to keep in mind that a diagram done by a Braille printer, 11 by 11 inch size, whether a diagram of a cat, or a diagram of the Empire State building is going to occupy roughly the same amount of space on that paper. So, the person approaching that picture tactilely doesn't have a clue about the frame of reference. So it's rarely productive to say `can you tell what this is?' It makes so much more sense to say, `This is a diagram of a church. You'll see the pointed steeple at the top' or one little bit of information to give the person a starting point to get some meaning from that picture."

Using a Computer to Supply Hidden Information

The concept of using computers to facilitate access to 2D information by blind people was pioneered by Dr. Donald Parkes, University of Newcastle, Australia, with the Nomad tablet. The Nomad is a touch-sensitive digitizing pad with a built-in voice synthesizer. It is attached to a computer through a standard serial port connection. A tactile picture is mounted on the Nomad pad, and information about various portions of the picture is contained in an electronic file in the computer. A user presses on some part of the picture, and information about that region is sent from the computer to be spoken by the speech synthesizer on the Nomad.

The Nomad is currently being sold in the US by the American Printing House for the Blind. They also sell Nomad pictures with the accompanying computer files that they have made to illustrate several subjects studied by blind children. Users can prepare their own pictures by any method and program in the information using software tools supplied with the Nomad. Anybody, sighted or blind, who can use a computer can prepare these computer maps.

Dr. Parkes has recently introduced two new computer programs that greatly extend the usefulness of the digitizing pad. AudioCAD is a computer graphics design program usable by both blind and sighted users. Blind users can design some things using voice and other audio information, but AudioCAD is most useful when used with the Nomad or other digitizing pads. The initial version of AudioCAD supports the Nomad and the Edmark TouchWindow. The TouchWindow is available from commercial computer hardware vendors and dealers who sell AudioCAD.

The second new program from Dr. Parkes is AudioPIX. This program allows blind or sighted users to construct computer files identifying various objects on tactile pictures mounted on either the Nomad or other supported digitizing pads. AudioCAD and AudioPIX are sold by Repro-Tronics and its dealers.

THE SCIENCE ACCESS PROJECT RESEARCH PROGRAM

The Science Access Project [8] was formed in 1995 under sponsorship of the National Science Foundation. Its goal is to enhance the ability of people with print disabilities to read, write, and manipulate information. In particular this project concentrates on information that has traditionally been difficult for people with severe print disabilities. This includes math equations, information normally presented in tables and graphs, and information presented in diagrams and figures that is often nearly impossible to describe in words.

The Science Access Project is developing several methods and computer programs. Those most directly concerned with tactile graphics are discussed briefly in this section.

Dotsplus

Dotsplus [9] is a method of presenting tactile information for blind readers with the same spatial formatting used for printed materials. It was developed largely for presentation of mathematical equations and scientific symbols used in text. It represents letters, numbers, and a few other symbols by braille dot patterns, but many symbols are represented by enlarged raised images of the ink-print symbol.

Dotsplus output is produced by making tactile copies of graphic computer files produced by a number of standard graphics programs, word processors, and page setting compilers. Authoring tools for producing Dotsplus are being developed and will be released by the Science Access Project when completed.

Any computer file that permits a global font change can be reproduced in Dotsplus with minimal editing. The Science Access Project and other organizations such as ICADD [10] (International Committee on Accessible Document Design) are promoting adoption of publishing standards to ensure that literature in the future will be available in electronic formats from which Dotsplus as well as other accessible document formats can be generated easily.

Dotsplus materials can be produced in bulk quantities by bulk graphic production methods described above. Swell paper is presently the only straightforward means of making single copy Dotsplus printouts.

Improving Computer Usability for Science, Engineering, and Math

The Science Access Project promotes computer programs that are accessible by multiple modalities. To date one product has been completed. This is an addition to the SCREEN [11] utility program that provides braille access to Unix applications that can be run in text mode.

The next product will be the TRIANGLE [8,12] program. TRIANGLE runs under the DOS operating system and is as trimodal (accessible visually, orally, or through braille) as possible with present technology. It is intended to be a tool for reading, writing, and manipulating information, including mathematical equations, complicated tables, and various kinds of graphs, diagrams, and tables.

A graphing calculator is part of TRIANGLE and its output can be "viewed" on the computer screen. It can also be heard as a tone graph, or felt by a moving braille icon as the x coordinate is varied. The graph may also be printed on a braille printer.

Flow diagrams, computer tree diagrams, and a number of other types of information typically presented graphically for sighted readers have been translated into "braille diagrams" that blind students have found fairly understandable. Some of the simpler diagrams of this kind can often be read using a refreshable braille display even though these displays show only one line at a time. TRIANGLE provides a braille reader for such braille diagrams.

Many such diagrams and most other graphical information is more easily understood if available as a tactile picture that can be viewed on a digitizing pad so that the computer can supply additional information. TRIANGLE includes this capability.

A number of translator programs will be made available in order to make TRIANGLE as useful as possible. At a minimum these will include programs to translate LaTeX, MS Word, and WordPerfect files into the GS [13] notation used by TRIANGLE, translation of standard spreadsheet files to the GS table form, and translations of the computer map files generated for figures by the Nomad and AudioPIX software.

Firms, Organizations, and Products

This section provides names, addresses, and contact information for a number of major US firms, organizations, and a few dealers for non-US firms manufacturing or selling products related to tactile graphics. The list is certainly not complete, and the author will be happy to include others in later versions of this paper if so requested. The product list is representative, not exhaustive. Contact the firm for dealer lists.

The state Commissions for the Blind also provide a good resource. Many sell products for the blind and maintain lists of local firms serving the blind. They can also provide local contact information for blind advocacy organizations. The Commission for the Blind usually has offices in the state capital and/or the major cities of the state.

Kit for making molds for tactile graphics: $228.75.
11 x 11 inch aluminum sheets for molds: 30 sheets for $17.65.
Aluminum rolls 150 feet by 11 inches: $57.15.
Starter Graphics kit: $24.95.
Nomad Tablet with standard speech synthesizer:
$1142.95 for educational institutions, $1505.95 for other customers.
Nomad Tablet with Keynote Gold Synthesizer:
$1644.95 for educational institutions, $2205.95 for other customers.

Regular duplicator, 8.5 x 11 or 11 x 11 inches: $2250. Large
frame duplicator, 13 and 7/8 x 18 and 5/8 inches: $2800. Regular
weight Braillon 11 x 11 inch size: 500 sheets for $45. Heavy
weight Braillon 13 and 7/8 x 18 and 5/8 inch size: 100 sheets for
$45. These are the extremes. Other Braillon sizes and weights
and various special supplies used for labels, etc. are also
stocked.

This firm manufactures and sells many products related to braille and tactile graphics including the Graph-it program (cost $49) that runs on their Braille Lite note taker. A PC version is also available.

The Braille Institute runs a printing operation that can produce bulk tactile graphics relatively inexpensively.

This firm offers design and production services for high resolution tactile graphic materials.

PC Braille fonts, both TTF and ATM, for Windows $99 Macintosh braille fonts $99.

Mr. Greg Nelson, Vice President for Marketing, may be contacted for information on possible uses of the company's forming systems for producing tactile graphics.

Small tracing wheel $15.75.
Drawing compass with wheel on end $28.75.
Freehand drawing stylus (bigger than a braille dot) $18.75.
Raised line drawing pad kit including compass, protractor,
square, 12 in ruler, drawing tool, and 100 sheets of mylar $118.

This company sold the Pixelmaster wax-jet color printer in the early 1990's. A modified version, called the Braillemaster, was capable of producing images with a thickness of approximately 0.01 inches. The product is no longer available, but the company supports it with supplies until they are exhausted.

A4 (8.25 x 11.5 inches) swell paper: 200 sheets for $220. B4 (10 x 11.5 inches) swell paper: 200 sheets for $280. Stereocopier: $6700.

This company sells a variety of modest cost software products. Several freeware or shareware programs and a free demonstration copy of their LowRez program for printing graphics on braille printers are available over the internet. People with ftp access to the internet can follow the KanSys prescription explained in a recent press release:

Our freeware and demos will be available from now on from the FTP site maintained by Phil Scovill on ftp.crl.com.

Type ftp ftp.crl.com and at the first prompt, type the word anonymous and press enter. At the second prompt, type in your complete email address and press enter. You will then be in the crl system. Change directories by typing cd /ftp/users/ph/phil/kansys and press enter. The Kansys welcome screen will pop up and list all available files for download.

e-mail: LSSGRP@aol.com
This firm carries a general line of supplies for the blind including the raised line drawing pad kit and a few other items related to tactile graphics.

Tactile Image Enhancer, used for processing swell paper: $895.
Thermo Pen, for writing directly on swell paper: $195.
8.5 x 11 inch "Flexi-paper" swell paper: 100 sheets for $98.
A4 "Flexi-Paper" swell paper: 100 sheets for $100.
Other sizes available on request.
Bumpy Pictures (AudioCAD and AudioPIX) software $425.
Bumpy Pictures with Edmark TouchWindow $625.

Computer programs for printing computer graphics files on the TSI Versaprint printers available free by modem from the TSI BBS using a standard computer communication program. BBS phone numbers are 415 335 1819 and 415 335 1820.

ACKNOWLEDGMENTS

The author is grateful to Ms. Jane Corcoran for explaining details of hand-preparation of variable-height tactile graphic materials. This paper was prepared with partial support by the National Science Foundation.

REFERENCES