System and method for print screen tonal control and compensation
View Patent ↗A print screen tonal control and compensation system and method are provided in which a compensated density curve is utilized to increase press predictability, performance, resources consumption, color variation, and quality. A computerized test pattern is generated, and by applying computer to plate technology, a printed press produces a printed test pattern. The test pattern is subsequently analyzed to identify the plugging point of the production run, and a compensated density curve is created to eliminate plugging within the production pattern. The density curve is then used to generate a compensated printing plate for use in a production press run.
1. A method for print screen tonal control compensation on a printing press, the method comprising:
providing a test screening pattern having a plurality of predetermined screening densities including a maximum screening density;
printing the test screening pattern in ink;
measuring an ink density of at least a portion of the printed test screening pattern using a densitometric meter;
determining the measured ink density of the printed test screening pattern at which the test screening pattern reaches a plugging point representing a solid screening; and
adjusting each of the ink densities of the printed test screening pattern above the plugging point, by a screening value sufficiently reduced to cause the printing press to print a screening pattern without reaching the plugging point prior to the maximum screening density of the screening pattern.
2. The method of claim 1 , wherein the maximum screening density represents a solid screening.
3. The method of claim 1 , wherein the printing press prints for a particular paper and a particular ink type and wherein providing a test screening pattern further comprises selecting the test screening pattern in dependence upon at least one of the particular paper and the particular ink.
4. The method of claim 1 , wherein providing a test screening pattern further comprises generating the test screening pattern on a computer.
5. The method of claim 1 , wherein the compensation is undertaken a number of times.
6. The method of claim 5 , wherein the compensation is undertaken until the measured ink density at which the plugging point is reached is not less than the maximum screening density of the test screening pattern.
7. The method of claim 1 , wherein the densitometric meter is one of a photospectrometer, densitometer, or combination thereof.
8. A method of calibrating a printing press, the method comprising:
generating a test screening pattern having a plurality of predetermined screening densities including a maximum density;
creating a printing plate to cause the printing press to print the generated test screening pattern;
printing the generated test screening pattern on the printing press;
measuring an ink density of at least a portion of the printed test screening pattern using a densitometric meter;
determining the measured ink density of the printed test screening pattern at which the printed test screening pattern reaches a plugging point representative of a solid screening;
creating a density curve for each of the screening densities of the printed test screening pattern above the determined ink density that reaches the plugging point, wherein the density curve represents a screening value sufficiently reduced to cause the printing press to print the test screening pattern without reaching the plugging point; and
creating a production printing plate to cause the printing press to print the generated test screening pattern in combination with the density curve.
9. The method of claim 8 , wherein generating a test screening pattern further comprises generating a test pattern having a plurality of screening densities including a maximum screening density representing a solid screening.
10. The method of claim 8 , wherein the printing press prints for a particular paper and a particular ink type and wherein generating the test screening pattern further comprises generating the test screening pattern in dependence upon at least one of the particular paper and the particular ink.
11. The method of claim 8 , wherein generating the test screening pattern further comprises generating the test screening pattern on a computer.
12. The method of claim 8 , wherein the calibration is undertaken a number of times.
13. The method of claim 12 , wherein the calibration is undertaken until the printed test screening pattern does not reach the plugging point.
14. A method of calibrating a printing press, the method comprising:
(a) generating a test screening pattern having a plurality of predetermined screening densities including a maximum density representing a solid screening;
(b) creating a printing plate to cause the printing press to print the generated test screening pattern;
(c) printing the generated test screening pattern on the printing press;
(d) measuring an ink density of at least a portion of the printed test screening pattern using a densitometric meter;
(e) determining the measured density of the printed test screening pattern at which the printed test screening pattern reaches a plugging point representative of a solid screening;
(f) creating a density curve for each of the screening densities of the printed test screening pattern above the determined density at which the printed test screening pattern reaches the plugging point, wherein the density curve represents a screening value sufficiently reduced to cause the printing press to print the test screening pattern without reaching the plugging point prior to the maximum density;
(g) adjusting the printing press in accordance with the density curve; and
(h) repeating steps (b) through (g) if the determined density at which the printed test screening pattern reaches the plugging point is greater than the maximum density.
15. The method of claim 14 , wherein the printing press prints for a particular paper and a particular ink type and wherein step (a) further comprises generating the test screening pattern in dependence upon at least one of the particular paper and the particular ink.
16. The method of claim 14 , wherein step (a) further comprises generating the test screening pattern on a computer.
17. A print screen tonal control and compensation system comprising:
a printing press adapted to print a screening pattern;
a densitometric meter adapted to determine an ink density of at least a portion of the screening pattern; and
a controller operatively coupled to the printing press and the densitometric meter, the controller comprising a processor and a memory operatively coupled to the processor,
the controller being programmed to generate a test screening pattern having a plurality of screening densities including a maximum screening density representing a solid screening,
the controller being programmed to cause the test screening pattern to be printed by the printing press,
the controller being programmed to cause the densitometric meter to determine a maximum ink density of the printed test screening pattern,
the controller being programmed to determine whether the maximum ink density of the printed test screening is a solid screening,
the controller being programmed compare the determined maximum ink density of the printed test screening with the maximum screening density representing a solid screening to determine a plugging point indication,
the controller being programmed to create a density curve for each screening density not less than the plugging point indication, and
the controller being programmed to apply the density curve to the test screening pattern.
18. The system of claim 17 , wherein the printing press prints for a particular paper and a particular ink type and wherein the controller being programmed to generate the test screening pattern in dependence upon at least one of the particular paper and the particular ink.
19. The system of claim 17 , wherein the densitometric meter is one of a photospectrometer, densitometer, or combination thereof.
20. The system of claim 17 , wherein the printing press is an offset printing press.