Method for making positive working lithographic printing plates

摘要

According to the present invention there is provided a method for making positive working lithographic printing plates comprising the image-wise exposure of a heat-sensitive imaging element with an infrared laser and developing said imaging element in a simple wet clean-out process. The imaging element is exposed on an internal or flatbed scanner with a laser having a pixel dwell time of less than 0.2 mu s to obtain a positive working printing plate having a high sensitivity.