3D printing in color has long been one of the greatest challenges for the industry. Now, researchers at the Fraunhofer Institute for Computer Graphics Research in Germany have discovered a way to use high-resolution, multi-material 3D printers to create colors that look more natural and are more precise than ever before. (In the photo below, only one of the apples was printed.) The colors also account for the translucency of the resins on which they might be printed. The researchers used algorithms to direct a Stratasys Objet 500 Connex 3printer to control the color and material of individual voxels, the three-dimensional pixels created by a single ink droplet.