Title and imprint from a lettered impression described in the British Museum online catalog (item no. 1876,1209.612).
"The portrait heads are based on thumbnail drawings made by Paul Sandby in the margins of print sale catalogues of the 1780s, now in an album in the Royal Library. They are described by A.P. Oppé in "The Drawings of Paul and Thomas Sandby at Windsor Castle" (Phaidon, 1947), pp. 83-85."--British Museum online catalog.
Library's copy is without letters; trimmed to plate mark.
Portrait heads of fifty-five men, mostly in profile, identified elsewhere as portraits of various print sellers, collectors, artists, etc., sketched by Paul Sandby while attending print sales in London.