In 1946 Escher became interested in the mezzotint, a technique that was new to him and fascinated him because of the possibility of obtaining extremely subtle gradations of light and dark. He produced several works based on this procedure. Among them are Mummified Frog, Crystal and Eye.
Dusk (Rome) from May 1946 is the first of these. He would only make eight mezzotints, the last one in 1951. The technique to create and print the plate was extremely demanding and frequently tedious, and very few prints could be created before the copper plate degraded. This led the as yet very patient and precise Escher to throw in the towel after a few years.