Details:
Summary:
Compared with the conventional printing method, the CTP technology can save manpower, chemical pollution, and production time for printers. The main considerations of a CTP investment consist of its production time, cost and dot-reproduction quality. Therefore, the stability of the CTP plates and their quality of tone reproduction are the two major concerns. This research was an experimental study in nature and intended to investigate the differences on the dot-reproduction quality and consistency among two major CTP plates and one conventional Presensitized (PS) plate in Taiwan's printing market. The results not only provide the printing industry in Taiwan with an evaluation of adapting CTP technologies, but also reveal the comparisons on the stability and quality of dot reproduction between CTP and conventional PS plates. The plate materials for the experiment included a Silver Halide plate, Photopolymer plate, and PS plate. A digital test form and control bar was designed for the two CTP plates, and a film generalized from the digital test form was developed for burning the PS plates. Forty plates for each type of the two CTP and PS plates were made and their images were measured by a plate-reading spectrodensitometer. The process capability based on the dot gain size, print contrast, and solid ink density was determined statistically. The results exposed the differences in the process capability based on the tone reproduction for the two CTP plates. The study also investigated the differences in tone reproduction between the conventional PS lithographic plate and CTP plates.