Autograph quotation signed.
Oblong 8vo (postcard). 1 page.
Inscribed to the German dermatologist Alwin Scharlau: "Auf Ihren Wunsch vom 12. d. M. sende ich hiermit meine Handschrift, die freilich sehr verschieden aussehen kann [...]".
A member of the artists' association "Malkasten" and a professor at the Düsseldorf Academy from 1902 onwards, Keller devoted himself to historical, landscape, marine and genre painting as well as portraiture. He also dabbled in writing, producing an allegorical chivalric play for the centenary of the Krupp factory in Essen in 1912.
Faint traces of a postmark near left margin. Self-addressed by the collector on the reverse. The Mecklenburg physician Scharlau (b. 1888) assembled a collection of artists' autographs by personal application.