Rembrandt produced etchings for most of his career, from 1626 to 1660, when he was forced to sell his printing-press and practically abandoned etching. Only the troubled year of 1649 produced no dated work. He took easily to etching and, though he also learned to use a burin and partly engraved many plates, the freedom of etching technique was fundamental to his work. He was very closely involved in the whole process of printmaking, and must have printed at least early examples of his etchings himself. At first he used a style based on drawing, but soon moved to one based on painting, using a mass of lines and numerous bitings with the acid to achieve different strengths of line. Towards the end of the 1630s, he reacted against this manner and moved to a simpler style, with fewer bitings. He worked on the so-called "Hundred Guilder Print" in stages throughout the 1640s, and it was the "critical work in the middle of his career", from which his final etching style began to emerge.