The Reproduction of Colours by Robert Steinheil, 1896 The engineer Robert Steinheil provides a reference system for the determination of three simple colors in order to obtain a given shade. The 150 boards, which are chromotypographed, account for nearly 15,000 different tones: “This book contains all the tones that can practically be rendered using the only three prints Yellow, Red, Blue. the tones that can be obtained by four prints (yellow, red, blue, black) and five prints (yellow, red, blue, black, varnish). ” Each color is presented in a chromatic circle, with differences of tone.
Source: The Reproduction of Colours