Fast, cheap and colorful 3-D printing

People are exploring the use of 3-D printing for wide-ranging applications, including manufacturing, medical devices, fashion and even food. But one of the most efficient forms of 3-D printing suffers from a major drawback: It can only print objects that are gray or black in color. Now, researchers have tweaked the method so it can print in all of the colors of the rainbow. They report their results in the ACS journal Nano Letters.