The EIA gray scale pattern is a standard 2″ square projection slide. It contains two parallel gray scales. The upper scale has nine nominally equal transmission steps while the lower contains the same number of nominally equal density steps. The transmission values range from 3% to 60%, corresponding to density values of 1.523 and 0.222 respectively. The slide is offered on both Chrome on Glass (CG) and Chrome on Opal (OP), and densities are achieved by a fine halftone pattern.