How I love research! One never knows what one will find when looking for something else.
A Printer’s Mark was a design used on the title page of a book. It was an emblem of either the individual or the printing house. The ceiling of the Jefferson Building, Library of Congress, is decorated with 56 of these devices, each about 1 1/2 feet high to be viewed from the floor. Capito (original Koepfel) is in the west corridor with other German printers. (I did not have a well-known mark, and I used several different ones and several variations.)
Capito invites the Reader to read more about this in The Library of Congress: the art and architecture of the Thomas Jefferson Building by John Y. Cole and Henry Hope Reed (pages 138-141).
Comments most Welcome via the tiny word below.