Notes pratiques sur l'orthochromatisme
A French photography manual by H. Quentin, published in Paris by C. Mendel in 1904, written as practical notes on orthochromatic plates for photographers. Its single picture is a three-part diagram of the solar spectrum: a band of dark Fraunhofer lines labelled A to H, a continuous rainbow strip, and a curve of sensitivity peaking in the middle, which a designer could borrow for a clean scientific chart layout with labelled horizontal bands.
