glossary of terms in map history
The intaglio technique of cutting lines directly into a copper plate to be printed; in nineteenth century, extended to steel plates as well. Also referred to as “line engraving.” The primary technique in the preparation of copper plates for the printing of maps.
The intaglio technique of covering a copper plate in a ground (a layer of acid-resistant substance), scratching through the ground to define the image, and then using an acid bath to etch the plate where exposed. In early modern mapping, often used for decorative highlights, especially in cartouches, but not for entire maps.