What are the possible reasons for the pattern size shift during bag printing?

1, When the packaging bag is printed, the longitudinal pattern size shrinks.Reason: Insufficient shrinkage margin. During printing, due to the influence of plastic film tension and heating and drying, the longitudinal dimension of the film shrinks greatly.Countermeasures: The size of the shrinkage margin should be appropriately increased during plate making to minimize the film tension. 2, When the packaging bag is printed, the pattern size in the longitudinal direction is elongated.Reason: Gravure size leaves too much shrinkage margin.Countermeasure: Set an appropriate shrinkage margin.