The GRL Dot Gain Model

The Plate/Press segment of any halftone printing process transforms halftone dots on film into halftone dots on paper, so that different shades of gray may be reproduced. During this process, the fractional dot area of these dots change. This phenomenon is called dot gain. Its study is an important quality control function, and is essential for proper tone reproduction. Because of their importance, dot gain curves have been modeled (put in equation form). This enables a parsimonious characterization of the entire dot gain curve by perhaps one or two parameters. Because of their importance, dot gain curves have been modeled (put in equation form). This enables a parsimonious characterization of the entire dot gain curve by perhaps one or two parameters. The GRL Dot Gain Model provides an excellent fit to actual data using only one or two parameters, and enables the calculation of the critical printing areas. This paper discusses the basic model, its inverse relation, solution for the critical printing areas, determination of the parameters, and cascading two curves. The mathematical development and experimental verification of the model is presented.