The hopeless pursuit of purification in cartographic communication: a comparison of graphic-arts and perceptual distortions of graytone symbols.

Simulation models are developed to determine the likely range of effects of edge growth caused by overinking during printing of dot-screen, parallel-line and crossed-line area symbols. Plausible amounts of edge growth, based upon experiences in printing Universal Product Code identifiers for food and household products, provide the basis for expanding the perimeters of the black image elements comprising an area symbol. Printing is at least as significant a potential source of error in cartographic communication as perception. A realistic strategy for coping with gray-scale distortions is presented in a series of guidelines. - Author