Parametar modified screen element “ Mutant r70” in security graphic

Individualized graphic products with screen elements (SE) have inspired us to carry on with further experiments with stochastic functions in the definition for creating screen elements. The paper gives images and definitions of individual new screening elements under stochastic function impact. Unreleased screen forms were tested for application in security individualized printing. New forms have been created that alter their basic image as their coverage definition increases. Due to this transformation of shape we have named them mutants. Mutating forms have two subdivisions. One is from the conventional set and the other from exponential advancing that appears either in initial gray level or in extreme coverage values. These forms have a high dot gain in printing, so they are not to be recommended for high screen ruling. Therefore we recommend them for the area visible to the human eye. Such screen systems are applied in jumbo posters and in graphic work with exceptionally strong messages. Due to the fact that these designs are subject to pseudo-random generating where the initiator is known (congruent method seed), they are ideal for individualizing neutral surfaces in documents. The security is based on secrecy of parameters in the congruent generator algorithm and in parameters with which the screen form is distorted.