Almost since the beginnings of photography, innovators have experimented with reproducing a color image. James Clerk Maxwell was the first to do so in 1861, using three projectors to cast a color image onto a wall.
George Eastman's company, too, worked at perfecting a color process, and in 1914 it announced its original Kodachrome. Unlike the Kodachrome available today (which, by the way, is a three-color process Kodak developed in 1935 and perfected in 1938), the original Kodachrome was a two-color process. In other words, it produced a color image from two black and white images rather than from three.
Black and white images to make color? Two- and three-color processes? Perhaps this doesn't make sense to you now. It will, though, after you check out the following activity, which is a basic explanation of color photography that uses Kodachrome's two-color process as an example.