The full color image was the results of the interference of the wavefronts of light from the one image upon the other.

To deliberately produce this phenomena, just load a camera with a panchromatic, black and white transparency film.  Panchromatic films render different colors as different shades of Grey.  Place any color filter over the lens and take a properly exposed photograph of a colored scene. Then advance the film to the next frame, and place a different color filter over the lens and take a second properly exposed photograph from the same spot.