Development of a System for the Prediction of Screen Printed Halftone Densities.

The majority of the scanning and film production for the screen printing process has tended to use standard lithographic calibration curves. These calibrations do not suit the graphic screen printing process, particularly at higher screen rulings, where mid tone and highlight dot loss is common. A comprehensive set of press experiments were used to establish the effect of the primary press parameters on halftone reproduction. These experiments produced vast amounts of data which was difficult to interpolate for different press conditions. In order to combine the results a software tool was developed for the prediction of halftone densities for the graphic screen printing process such that the film positives can be produced to extend the tonal range on the process. This paper describes the formulation of the algorithms and process models used to combine the experimental data, validation studies of the software algorithms and finally the development of software package which can be used to improve quality and reduce down time. The concept developed can be applied to any printing process for which sufficient data is available.