| Abstract:This paper evaluates the print mottle in the prints of different kinds of paper such as color offset newsprint, art paper and single coated paper. Results showed that the optimized conditions for the two kinds of newsprint A & B are different except for the ink amount of 0.1 mL. The optimized conditions of the single coated paper F and art paper E are as follows: ink amount 0.2 mL, printing pressure 325 N, printing speed 0.4 m/s. There exists inconsistent correlation between objective quantitative assessment of mottling and subjective evaluation for F, however there is good correlation for E. The optimized conditions of the single coated paper H are as follows: ink amount 0.05 mL, printing pressure 525 N, printing speed 0.3 m/s. Results show that there exists consistent correlation between 2 groups and 4 groups subjective evaluation of mottling. Among the three digital analysis methods, power spectrum analysis correlates the most closely with the visual results, then the PTS method. And the grey value method correlates the least. So the power spectrum analysis and the PTS method are expected to be a new method for evaluation of the print mottle. |
