German painter, engraver, and the inventor of the mezzotint printing method.

Siegen spent most of his early life in the services of the landgravine Amelia Elizabeth and the landgrave William of Hesse-Kassel. He lived in Amsterdam from 1641 to about 1644, when he was supposedly influenced by Rembrandt. Later he served the elector of Mainz and the duke of Brunswick in Wolfenbüttel, where he is mentioned for the last time in 1676.

His earliest dated mezzotint was a portrait of Amelia Elizabeth (1642); in its dedication he claimed the invention of the process, which he described as engraving by dots rather than lines and in which he used a small roulette, a tool with a fine-toothed wheel. Seven known rouletted mezzotint plates by Siegen survive.