Coloring test on Shapeways' White Strong & Flexible 3D printing material, using Winsor & Newton watercolors and Letraset ProMarkers. With watercolors it is possible to make soft gradients between colors, as well as sharp edges. Markers blend slightly, giving softer edges, and can be used to make gradients as well, similar to how they react on paper. Watercolors can be washed out of the printed object almost entirely using water, marker colors don't change at all under water.
"Watercoloring Shapeways' White Strong & Flexible" using watercolors (3D Printing)