A method of determining trapping, i.e., spreading or choking, in color boundary areas in a printed image, includes characterizing with respect to register behavior one of a printing machine and a printing machine type, respectively, performing a printing; determining the printing-machine specific register behavior with knowledge of influencing factors relating to the color to be printed and the printing material to be printed on for the job being printed; calculating minimum required spreadings and chokings, respectively, while taking a safety margin into account; and taking into account minimum geometric overlaps in producing an original.