The Plate Side of Computer-to-Plate: Printability and Runnability.

This presentation will focus on the findings at GATF that many of the thermal CTP plates printing in the last Tech Alert CTP study displayed either no gain, or even a slight sharpening, of the midtone physical dot area from plate to print. A study of the differences in the imaging mechanism did show a preponderance of sharpening for positive working plates. Further investigation into the physical dot structures of the plates, though, failed to reveal a physical characteristic of the dot or the coating that might account for this effect. To the contrary, it was observed that the physical structure of the coating did not play a significant role in decreasing the amount of physical dot gain traditionally attributed to the press. It is suggested from these observations that the surface chemistry of the hydrophilic and hydrophobic areas, as well as the press conditions (ink, paper, etc.) were primarily responsible for this effect.