Application of CTP: Printability Test Procedure for Plates

In the heyday of the traditional PS plate, the test process of the plate sales agent came to the plate making room with a box of printing plate and a barrel of developer. The developer was added with a new developing solution, and exposure testing was performed. Take a set of plates and place them on the press.

With the advent of digital CTP plates (thermosensitive plates or other digital plates), the situation has changed. Digital plates are part of an interdependent CTP system that includes printing plates, processors, processing solutions, platesetters, RIPs, and solutions for printers and printers. Using current work to test new digital plates requires that many units of the system be readjusted so that the plates are suitable for printing jobs.

The adjustment of equipment and plates generally takes one day. This includes the testing of the equipment by the manufacturer of the platesetter, and the supplier's testing of the plate processing conditions and developing conditions. As well as the printability adjustment of the plate.

Therefore, when it comes to testing new digital plates, the accepted method for most people is to let plate makers and plate manufacturers image a set of plates according to standard test methods (such as the North American GATF digital test method). Items that need to be adjusted generally include laser focusing, laser intensity, laser beam slope, and dot gain curve. This requires repeated output of the plates to adjust the platesetter to optimum use.

If the test method works well, the next step to consider is to use the digital plate for on-press printing. This allows us to evaluate the initial characteristics of the printing plate and the compatibility of the plate with the conditions of the printing press (washing, ink fountain, cleaning agent). Because the printability of digital printing plates is not the same as the traditional PS version, operators are required to re-adjust their ink-water balance.

After one day of testing, you can officially start using digital plates. However, since digital plates are still new technologies for most printers, the accumulation of experience in actual printing is essential.