The first principles of photography : an elementary treatise on the scientific principles upon which practical photography depends
An 1892 London handbook by Clement J. Leaper, published by Iliffe & Son, that explains the optical and scientific principles behind practical photography. The pictures are plain black-and-white line diagrams of light rays converging through lenses, reflecting off mirrors, and passing through a camera-like viewing setup, drawn with labelled points and dashed guide lines. A designer could take from them a clean, technical schematic style: thin strokes, lettered reference points, and radiating ray paths suited to scientific or instructional graphics.
