PHOTOGRAPHIC SIMULATION OF DENSITY DIFFERENCES AS CHANGES OF LINE DIRECTION

摘要

ABSTRACT OF THE DISCLOSUREThe invention relates to a photographictechnique for generating a line pattern for use increating medallion effects on printed documents or foranti-counterfeiting purposes and the like. A high-contrastline screen negative is prepared and a positive generatedfrom the negative. The positive is then superposed onthe negative but offset therefrom by the width of athin line of the resulting image. The combined linepattern creates a medallion effect when the line spacingis comparable in dimensions to the image detail. Theresulting pattern may also be used in conjunction with afinding screen or superimposed line pattern to regeneratevisual information that appears in hidden or subdued formin the photographic pattern per se.