In the printing process, a key indicator that people often pay attention to is overprinting, as the waste caused by inaccurate overprinting often accounts for a large proportion of the total waste. Although flexographic printing machine manufacturers have provided a good foundation for precise overprinting in their design and processing processes, and automatic monitoring systems have also provided guarantees for accurate overprinting, the technical level and proficiency of operators also have a significant impact on overprinting accuracy. If some adjustments can be made for the convenience of overprinting when designing ink maps, it can greatly reduce the difficulty of printing and reduce the scrap rate.
Misalignment when there is no trapping (left) and when there is trapping (right)
The simplest way is to design the original ink manuscript with reversed white characters as much as possible, or to create a reversed white outline by hollowing out between two colors, or to cover the edges of the two colors with a third slightly thicker dark outline. For printing of finer prints, trapping technology can be used, and the amount of trapping depends on the accuracy of the printing machine, the quality of the paper used for printing, and the level of the operator.
Trapping processing is easy to implement on a computer. Without a computer, only ready-made color separators can be used. A specialized trapping modifier can be used to input the value of the trapping amount, and the machine will automatically generate a film that has undergone trapping processing. If there is no trapping processing machine, a transparent spacer can be placed between the color separation film and the copy film, and a single point light source copy machine can be used for exposure to obtain a similar effect of the film.