Offset printing positives prodn. method - using double exposure to register screen then image followed by development

摘要

The prodn. method is for offset printing screen positives. A first copy of the screen is copied onto reversal or diazo film. The second copy is also copied onto the same pre-exposed reversal or diazo film and then it is developed. The printing positive contains only required information because the flexibility of this two copy method allows exclusion of the unwanted.