Quadrille paper is a 20 lb. basis, acid-free layout bond, with a 4x4, 8x8 or 10x10 to the inch grid printed in a non-reproducible blue ink on one side. The paper has a smooth opaque surface for pencil & ink with good erasing qualities, and can be used with copiers, inkjet & laser printers. This paper is commonly used by draftsmen, architects, and engineers for plotting graphs, drawing diagrams, statistical data, etc.