By Jason Matthews

Cultures have used ivory for crafting artwork since around 1800 BCE. This material has been great for art patrons over the centuries, but not so much for the elephants. Due to an alarming decline in elephant populations, thankfully, an international ban on the ivory trade was introduced in 1989. This ban saved the elephants from extinction but left thousands of priceless works of art to decay with no way to renovate them.

It is saddening to see how few of these magnificent creatures are left in the wild - Image Credit: CreativeNature_nl via iStock/Getty Images - HDR tune by Universal-Sci

Art restorers have had to settle for bone, shells, horns, and plastics as ivory substitutes, none of which are ideally suitable. However, a team at the Institute of Materials Science and Technology at TU Wien in Vienna believe they have created the ideal alternative.

TU Wien and its linked 3D printing company Cubicure GmbH have developed the new material, called "Digory," as a viable alternative to other ivory substitutes. Ivory has a particular luster, translucency, and coloring that traditional replacements do not. The team wondered if, using the latest 3D printing technology, along with the proper base materials, they could make a material that successfully reproduces the unique characteristics of ivory. If successful, the technology could potentially maintain important artifacts and artworks in their original condition indefinitely.

On the right: The new material Digory, ivory on the left - Image Credit: TU Wien via Eurekalert

The team worked in cooperation with the Archdiocese of Vienna's Department for the Care of Art and Monuments and Addison. Prof. Jürgen Stampfl of TU Wien explained, "The research project began with a valuable 17th-century state casket in the parish church of Mauerbach. It is decorated with small ivory ornaments, some of which have been lost over time. The question was whether they could be replaced with 3D printing technology."

Drawing from their previous experience with 3D printing similar materials for the dental industry, the team set about the task of creating Digory. "We had to fulfill a whole range of requirements at the same time," says Thaddäa Rath, part of the research team. "The material should not only look like ivory, the strength and stiffness must also be right, and the material should be machinable."

After much experimentation, they found the right combination of materials. They precisely mixed microscopic calcium particles with a special resin and silicon oxide powder. Next, using the hot lithography process, they 3D printed the material, layer by layer, into the desired shape. Finally, they hardened the finished product using a UV light laser.

Chess pawns made from ivory, with adjusted color and texture to mimic ivory. - Image Credit: TU Wien via Eurekalert

For the finished product to have the desired look, the mixture must be exact. Thaddäa Rath explains, "You have to bear in mind that ivory is translucent. Only if you use the right amount of calcium phosphate will the material have the same translucent properties as ivory. Later, the color of the object can be touched up - the team achieved good results with black tea. The characteristic dark lines that normally run through ivory can also be applied afterwards with high precision."

Digory can be printed with incredible precision, replicating original designs to the finest detail without the need for hours of crafting by a specialist restorer. It can still be easily machined and carved manually, if required, and is visually almost indistinguishable from natural ivory. The team hopes restorers will embrace this new technology as a superior ivory substitute, and they are looking into other possible applications.

For more detail about the research, be sure to read the paper published in the science journal 'Applied Materials Today,' linked below.

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