19th-century art form revived to make tactile scientific graphics for blind people

In the 19th century, an art form known as lithophanes was in vogue in Western Europe. These thin engravings are usually made from translucent materials such as porcelain or wax. When backlit, a glowing 3D image will appear that will change its characteristics in response to changes in the light source. Now researchers have revived this art form to create tactile graphics to illustrate scientific data that glow in high resolution. According to a recent paper published in the journal Science Advances, these lithophanes are accessible to the sighted and visually impaired, making them a versatile tool for visualizing scientific data.

“This research is an example of art making science more accessible and inclusive. Art saves science from itself,” said co-author Brian Shaw, a biochemist at Baylor. “The data and images of science—like the stunning images coming out of the new Webb telescope—are inaccessible to blind people. However, we show that thin translucent tactile graphics, called lithophanes, can make all these images accessible to anyone, regardless of vision. As we like to say, ‘data for all’.”

The word “lithophane” comes from Greek litho (stone or rock) and fainein (to cause to appear), popularly translated as ‘light in stone’. The roots of the art form may date back to ancient China, about 1,000 years before the Tang Dynasty. (Historical sources describe paper-thin bowls with hidden decorations.) But to date, actual lithophanes are not known to have been in China before 1800.

Exactly who perfected the lithophane manufacturing process is still debated among historians. A common 19th-century process involved etching a 3D design onto a thin sheet of translucent wax or porcelain using traditional relief and intaglio printing techniques. More light will shine through the parts of the thread where the wax is thinnest.

These lithophanes were between a sixteenth of an inch and a quarter of an inch thick. They were displayed as plaques hung in windows or in front of shields with lighted candles behind them as a source of light. Lithofans can also serve as night lights, fireplace screens, tea warmers or ornaments engraved with erotic images. American industrialist Samuel Colt filled his home in Hartford, Connecticut with more than 100 lithofans and commissioned 111 lithofan versions of his photograph to give to friends and associates.

The technique fell out of favor after the invention of photography, but the advent of 3D printing has revived interest. Today, lithophanes are typically made with plastic 3D printed from any 2D image that has been converted to 3D topography, according to Shaw and his co-authors, which they did with free online software. Four of these co-authors were blind from birth or childhood, yet successfully completed their Ph.D. But they are rare examples. Finding a way to create universal tactile science graphics that can be used by both blind and sighted people would remove a long-standing barrier that has kept many visually impaired people out of science.