Ralph Clifton Smith:

18) Gustav Kruell. American Portrait Engraver On Wood.

New York 1929

The author was a curator of the Division of Graphic Arts and Photography of the Smithonian National Museum of History and Technology, which was founded by Sylvester Rosa Koehler in 1886. Ralph Clifton Smith, who had also published valuable bibliographies of the oeuvres of Timothy Cole and Henry Wolf, repeatedly cites Linton’s appraisals of Kruell’s expressive mode of portrait engraving.

Kruell had been trained in Germany in the Düsseldorf workshop of Richard Brend'amour, he had founded his own firm in Stuttgart and was forced to emigrate because of his socialist commitments. He became the founder and president of the Society of American Wood Engravers. Because of his free artistic graver manner Linton doesn’t count him to the New School.