Map of the world by Frederick de Wit, produced circa 1670 in Amsterdam. This is the first edition of this map, which can be identified because it lacks a decorative border. This copper engraving is one of the most beautiful ever produced. The process of engraving copper, or the intaglio process, requires printing ink to fill up the cuts into the copper. A sheet of paper is then pressed onto the copper plate, which creates an image and a mark around the edge, called a plate mark. Repeated impressions, above a few hundred, gradually lose their sharpness because of the softness of the copper. This particular map shows California as an island, a common mistake of the period, but which adds to the map's charm and value.