Although Gilbert Spencer’s principal works were painted in oils, he also produced an enormous number of works on paper, and those included in this catalogue are only a representative selection, rather than an exhaustive list. Spencer used pencil, pen and ink, and watercolour for different purposes, according to the subject matter. His watercolour landscapes were finished pieces intended for sale rather than preparatory studies for oil paintings. He almost never painted the same view in oils and watercolours, with one exception, at the request of his young niece. For his figure paintings, by contrast, he worked up the compositions in pencil and watercolour, before squaring them for transfer to canvas, and rarely created stand-alone figure paintings in watercolours.

Spencer also made many portraits in pencil, sometimes on commission, but more often of friends, family, and his own features. He illustrated several publications, most notably The Ten Commandments (Mill House Press, 1934), designed an annual family Christmas card, and expressed his warm sense of humour through gently satirical drawings, mostly for pleasure, but in the case of the Home Guard series of watercolours (1941-2, private collections), for exhibition and sale.