PS plateau quality (below)

Sample 2 has a relatively steep peak top and a medium wavelet peak. When the contour level intercept is 10%, the contour support length is 2%. Sample 3 has a sharper peak on the top of the sand, and a more abundant wavelet peak. The 80mm magnifying glass is used to observe the layout of the coated photoresist, the local microcosmic coating is uniform, the uneven thickness of the microscopic glue is not visible, or the base color of the plate is not visible. The phenomenon, that is to say sample 2 and sample 3 has no platform structure, or the platform is small (diameter is less than or equal to 5m). Use a standard test strip to test the photographic performance of this version. The resolution can reach 10m, and even 8m can be restored.
The author believes that a high-resolution PS version, from the perspective of plate-based sand grain analysis, does not entirely depend on the size of the Ra value, the key lies in the state of the sand microstructure.
3. The analysis of the average distance between the peaks and the valleys of sand and sand directly relates to the fact that there are several sand grains and valleys supporting the graphic and network points during printing. That is, when the Ra value is constant, the average distance between peaks and valleys (Sm) is small, and the dots are supported. There are many peaks and valleys, and the strength of the outlets is large. However, the value of Sm cannot be too small, otherwise it will make the concave valley of the sand narrow, affect the same water retention rate, and increase the chance of being dirty on printing.
According to the sampling length (the national standard GB/T1031-1995 stipulates that Ra = 0.1-2.0m, the sampling length = 0.8mm) and the density D value of the profile peak within the sampling length (Japanese standard uses the sand peak height and valley depth respectively exceeds 0.635 The Pc number of m) can calculate the Sm value of the above three samples and the number of peaks and valleys supporting 2%, 3%, 5% dot. See Table 2 for details (using the dot frequency of 60 lines/cm as an example).
Sm 2% Dot diameter 3% Dot diameter 5% Dot diameter Sample 1 7.62m 3.5 peak valley support 4.3 peak valley support 5.5 peak valley support sample 2 10.2m 2.6 peak valley support 3.2 peak valley support 4.1 peak valley Supporting sample 3 9.20m 2.9 peaks and valleys support 3.6 peaks and valleys support 4.6 peaks and valleys support From the data of sample 1, the average distance (Sm) is small, and the number of peaks and valleys supported on the diameter of the dot is large, so it should be ideal sand. Structure. However, from the following tp% curve analysis, it can be clearly seen that the sand grain microstructure of Sample 1 affects the water content of the valley, which is not as good as Sample 2 and Sample 3.
4. Analysis of the support length rate curve According to the horizontal intercept-support length rate curve of the three samples, the corresponding data can be counted in Table 3. From the statistics, it can be seen that the grain microstructure of sample 1 is not only broad (the peak width is 0.23m when the horizontal intercept is 10%), but also the peak is thick and fat, and the peak of the center line (50%). Waist width has accounted for 80% of the average spacing (6.096m), and the average peak height above the centerline is Rpm = 1.82m, apparently the sand is too coarse. Although its grain is strong and its strength is high, anti-extrusion (pressure between the printing plate cylinder and the blanket cylinder) is small, the concave pit space is narrow, the water content is low, the water retention performance is also not good, and it is easy to dry when printing. . Samples 3 and 1 have diametrically opposite grain structures, and do not believe that the peaks are steep (the average width of the peaks at the horizontal intercept of 10% is only 0.092m), and the mean width at the peaks of the peaks is also narrow, with the centerline (horizontal The average width of the peak waist at the intercept of 50% only accounts for 40% of the average distance (3.68m. Obviously, the pit structure of the plate has a large pit space and a large amount of moisture, which easily meets the ink-water balance during printing. Needs, but the water retention performance is also good, printing is not easy to dry version.Statistics of sample 2 shows that its performance in this area is in the middle state.
Table 3 Peak Width Values ​​at Different Level Intercepts of Three Samples

Horizontal intercept 10% 20% 30% 40% 50% 60% 70% 80%
Tp% Peak width m Tp% Peak width m Tp% Peak width m Tp% Peak width m Tp% Peak width m Tp% Peak width m Tp% Peak width m Tp% Peak width m
Sample 1 3 0.23 12 0.91 34 2. 59 60 4.57 80 6.10 92 7.01 98 7.47 99 7.54
Sample 2 2 0.20 7 0.71 19 1.94 35 3.57 58 5.92 79 8.06 93 9.49 98 10
Sample 3 1 0.09 4 0.37 8 0.74 20 1.84 40 3.68 65 5.98 81 7.45 95 8.74

In short, to determine the quality of the PS version, first of all to deal with the various parameters of the sand, whether it meets the requirements of the printing ink balance, if the sand structure is not ideal, the oxide film produced on the surface strength is no matter how good, sensitive The plastic item index is ideal and can not meet the needs of printing.