Blind people will read graphs with their fingers

Braille was already available for blind people to read text. A technique has now been added to “view” drawings, charts and figures. American engineers use the 3D printer to represent the characters in relief.

It is estimated that 40 million people worldwide are blind or partially sighted. Not only in everyday life, but also in science, they encounter additional obstacles compared to people who can see well. They can’t see the numbers in books and newspapers, and they don’t get the PowerPoint presentation at the department meeting.

3D printer

The scientists and engineers of certain universities in the United States are not resigned to it. They have developed a technique allowing blind and visually impaired people to access scientific results presented visually.

They use the 3D printer to make so-called lithophanes, they write this week in the freely accessible scientific journal Scientific advance. These are thin slices of plastic, of varying thickness. Blind people can feel the bumpy surface and get information, such as a graph or a reading from a measuring device. At the same time, lithophane is also useful for sighted colleagues. They can hold the image up to the light and thus visualize the original figure based on the light-dark differences.

art form

Although this application is new, it is possible to make lithophanes an art form several thousand years.

Lithophanes are images cut or carved into a surface (traditionally thin porcelain or wax) that appear opaque when lit from the front, but glow like a 3D image when lit from behind . Indeed, the thinnest parts of the sculpture allow more light to pass than the thicker parts. Here is an example (source: Wikipedia):

Photos: public domain

come back

With the emergence of photography in the 1800s, lithophanes quickly became less popular. But in recent years they have made a modest comeback, write fellow scientists an accompanying article, because 3D printing makes it cheap to manufacture such a work of art. They estimate that a lithophane should only cost 50 plastic cents for the 3D printer.

test subjects

The inventors of scientific lithophanes tested in practice the ability of blind people to read 3D printed graphics. To that end, they presented the plastic slices to a group of test subjects, some of whom were blind, some had sight, and some had blindfolds. In most charts, blind people read them better than sighted people. This suggests that this new application of lithophanes is appropriate to allow all scientists to share the information contained in graphs and figures.

Like a deck of playing cards

The authors of the attached article also give an idea to the inventors of the new technique. While consultation in research groups is usually done by means of short PowerPoint presentations, the blind must miss the graphic part.

“So it makes sense to consider converting every PowerPoint slide in a presentation to lithophane so that audience scientists can hold the images in their hands like a deck of playing cards,” they write in their article. This way every colleague can look at the graphs and measurement results and the scientific enterprise becomes truly inclusive for the blind and visually impaired.

Opening photo: example of a 3D printed SDS-PAGE plot, the result of a protein separation technique. Photo: Jordan Koone and Bryan Shaw

If you found this article interesting, subscribe to our free weekly newsletter.