The Braille Monitor                                                                                       May 2003

(back) (next) (contents)

Tactile Images and You:
A Comparison of Thermal Expansion Machines

by Robert S. Jaquiss

Robert Jaquiss
Robert Jaquiss

From the Editor: Robert Jaquiss is one of the technology experts working in the International Braille and Technology Center for the Blind. In the following article he provides important comparisons among the four pieces of equipment the IBTC has for creating tactile graphics. This is what he says:

The use of tactile graphics materials is a growing component in the education of blind children. Parents, teachers, transcribers, and students need to be aware of the available technologies. This article is an introduction to one of the technologies for producing tactile graphics.

When I was a student in the early '60's, the only practical way to produce tactile graphics was to have them handmade. For simple diagrams my mother would trace the drawing on the back side of a piece of Braille paper, remove the thread from her sewing machine, set it on a straight stitch, and run the piece of Braille paper through the machine. The result was a nice dotted-line drawing.

She could also use a tracing wheel and the point of a drawing compass. Other tactile materials could be made by making a collage of sandpaper, cloth, string, and whatever other tactile materials were at hand, gluing them all to a piece of paper. Making diagrams with these methods could take hours, and the results were often fragile. Over forty years later some tactile materials are still made the same way.

A New Technology

In recent years schoolbooks have presented more and more information graphically, and teachers are using visual approaches in classrooms. Increasingly blind students are called upon to learn how to use tactile graphics, and teachers and other producers of educational materials must learn how to produce such graphics.

One way to produce tactile graphics is by using a thermal paper expansion machine. The International Braille and Technology Center (IBTC) has four of these: the SwellForm from American Thermoform; the Picture in a Flash (PIAF) from Pulse Data HumanWare; and the Tactile Image Enhancer (TIE) and TIE Junior from Repro-Tronics.

To produce an image using one of these machines, you need a special kind of paper to feed into the machine: thermal expansion paper. There are two types: Flexi-paper from Repro-Tronics and SwellTouch from American Thermoform. The Flexi-paper is fabric-based and has a matte surface. It is very flexible and can tolerate folding. The SwellTouch paper is paper-based and has a smooth paper surface on one side and a matte finish on the other side. Folding SwellTouch paper will cause creasing. Thermal expansion paper is expensive--ranging in price from $.85 for one 8.5-by-11-inch sheet to $1.70 for one 11-by-17-inch sheet. A slight reduction in price is available when large quantities are ordered.

The basic process for producing tactile images on a thermal paper expansion machine is simple:

1. Using any graphics program or clipart source, prepare a line drawing.

2. Print the drawing on the front of the thermal expansion paper. You can use a photocopier to transfer an image from plain paper to thermal expansion paper, or you can use an inkjet or laser printer to print directly from a computer to the expansion paper. However, caution must be exercised when using a photocopier or laser printer to make an image directly on thermal expansion paper. If the paper gets too hot, it will expand inside the photocopier or laser printer, possibly causing a jam or damaging the equipment. For this reason we recommend an inkjet printer.

3. Pass the thermal expansion paper face-up through a thermal paper expansion machine.

While the process for actually producing an existing image is easy, the issues involved in the design of a good tactile image can be complex. It takes practice to learn how to design useful tactile graphics. Here are some basic concepts to keep in mind:

1. Keep the image simple. Include only those features the user needs to see.

2. Be consistent with Braille labels and other symbols. When looking at a tactile graphic, imagine that you have never seen this image before. Ask yourself, do the labels make sense, and would I find this image useful in the context for which it is intended?

All the machines will process SwellTouch paper and whole sheets of Flexi-paper, but only the TIE or TIE Junior should be used to process smaller sheets of Flexi-paper. In my tests Flexi-paper was more flexible than SwellTouch paper, and smaller pieces tended to jam in the SwellForm and PIAF machines because they do not use solid surface rollers to move media.

While the controls on all of the machines are essentially the same (each has a power switch and a heat adjustment), one should consider the differences before purchasing or using these machines. For example, in order to open the cover of the TIE, you must first remove the power cord. By contrast, you do not need to disconnect the power cord of the SwellForm machine before opening it. It does have a safety switch, but it is still possible to activate the machine when it is open, creating a possible safety problem. You cannot open either the PIAF or the TIE Junior at all, which means that jammed materials must be pulled out of them, leading to possible operational problems.

There are also differences in the heat adjustment controls among the machines. The TIE and TIE Junior have very easy-to-use pointers. The PIAF has a groove in the top of the knob, and the knob has resistance when it is turned. Therefore, your heat setting will stay put if the machine is bumped. The SwellForm knob has no tactile pointer. All the machines except the PIAF have power switches in easily accessible places. The PIAF's switch is on the back of the machine.

When considering safety, ease of use, and flexibility of materials used, I rank the Repro-Tronics machines, the best designed, followed by SwellForm and PIAF. Following is a rating table summarizing the results of my experience with the machines and the discussion above. The scale is from one to three, with three as the top mark:

                                                       Rating Table

                                Characteristic� PIAF� SwellForm� TIE� TIE Junior

                                Safety��� ������������1���������  2���������������  3���������  2

                                Ease of Use������ 2���������� 2���������������   3���������� 2

                                Flexibility��������  1����������� 1���������������   2���������� 1

                                Price�            $1,299����  $985��������   $995������� $395

All these machines should be used only by adults or with adult supervision. Work areas should be kept free of loose paper, scraps, and dust.

One other device is relevant to the thermal paper expansion method of producing tactile graphics. It is not a machine but the Thermal Imaging Pen from Repro-Tronics. This pen is a tool that allows a person to draw on thermal expansion paper by hand. The tip of the pen gets very hot, and when it is brought into contact with the paper, it produces a raised image by causing the paper to swell at the point of contact. This device should also be used with adult supervision.

With the right designs, these machines and devices can open up a world of tactile images for a blind user. Recently, when NASA was here at the center promoting our collaborative project, Touch the Universe, a book with tactile images of the galaxy, we demonstrated these machines to over forty children, using a variety of images related to astronomy. In a classroom with a creative and motivated teacher, even simple tactile graphics can increase a blind child's understanding of the lessons his or her classmates experience visually. Thermal expansion paper is not the ultimate solution for producing tactile graphics. It is one solution and, when properly used, should be very beneficial. Thermal expansion paper is best used for reproducing line art, graphs, outline maps, and other similar items. Thermal expansion paper is easy to use, so experiment and see what results you get preparing many touching experiences.


American Thermoform Corporation: <>

Pulse Data HumanWare: <>

Repro-Tronics: <>

The sites listed below are additional resources:

Adapted Graphics: <>

Purpose: The Adapted Graphics list's purpose is to discuss graphics designed for the blind and visually impaired. This includes the development of tactile graphics and other types of information designed for the blind and visually impaired. The list is for anyone interested. See the Web page for subscription instructions.


TAEVIS Online: Tactile Access to Education for Visually Impaired Students. TAEVIS is operated by Purdue University, and its materials are produced for Purdue students. TAEVIS does, however, sell copies of its diagrams, and the site also provides much in-depth information on tactile graphics.

(back) (next) (contents)