In the early 1960s, influenced by films, television, and billboard advertising, Katz began painting large-scale paintings, often with dramatically cropped faces. Ada Katz, whom he married in 1958, has been the subject of over 250 portraits throughout his career. To make one of his large works, Katz paints a small oil sketch of a subject on a masonite board; the sitting might take an hour and a half. He then makes a small, detailed drawing in pencil or charcoal, with the subject returning, perhaps, for the artist to make corrections. Katz next blows up the drawing into a "cartoon", sometimes using an overhead projector, and transfers it to an enormous canvas via "pouncing"—a technique used by Renaissance artists, involving powdered pigment pushed through tiny perforations pricked into the cartoon to recreate the composition on the surface to be painted. Katz pre-mixes all his colors and gets his brushes ready. Then he dives in and paints the canvas— wide by high or even larger—in a session of six or seven hours.