As an application of the theoretical concepts introduced thus far, we present in this chapter the interesting problem of moiré minimization, namely, the question of how to find stable moiré-free combinations of several superposed dot-screens. Historically, this question finds its origin in the field of colour printing; and indeed, this context will be used here as our principal setting to illustrate the problem. Simpler cases involving only two superposed screens may also find their use in some other applications, such as the minimization of moirés which occur when a halftoned image is scanned by a digital scanner or sent by fax.
In general, three different strategies can be used to fight undesired moiré patterns: avoiding moirés, i.e., taking measures to prevent their generation; minimizing moirés, i.e., finding layer combinations which minimize their appearance; and removing moirés, i.e., getting rid of them once they already exist. Methods for avoiding moirés...