I experimented to get colour image from B&W film. To get one colour image, I took three identical photos through a red filter, one through a green filter, and one through a blue filter. The resulting three photographs were projected through filters of the same colors and exactly superimposed on a screen that visually combined the three into one full-color image. This method of color photography used by Prokudin-Gorsky was first suggested by James Clerk Maxwell in 1855 and demonstrated in 1861.