Block printing. See under Block. -- Printing frame (Photog.), a shallow box, usually having a glass front, in which prints are made by exposure to light. -- Printing house, a printing office. -- Printing ink, ink used in printing books, newspapers, etc. It is composed of lampblack or ivory black mingled with linseed or nut oil, made thick by boiling and burning. Other ingredients are employed for the finer qualities. Ure. -- Printing office, a place where books, pamphlets, or newspapers, etc., are printed. -- Printing paper, paper used in the printing of books, pamphlets, newspapers, and the like, as distinguished from writing paper, wrapping paper, etc. -- Printing press, a press for printing, books, newspaper, handbills, etc. -- Printing wheel, a wheel with letters or figures on its periphery, used in machines for paging or numbering, or in ticket-printing machines, typewriters, etc.; a type wheel.