1609-c. 1680

German engraver and painter who in 1642 invented the mezzotint process for printing in graduated tones. Siegen, who described his method as one of engraving by dots rather than by lines, used a small roulette or fine-toothed wheel to achieve the desired effect. For years he kept his method a secret, before revealing it to Prince Rupert of the Palatinate, a patron, in 1654. Eventually the process made its way to engravers in England, who adopted it to a much greater extent than their counterparts in other countries.