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FLEXO Magazine : January 2009
TECHNOLOGIES & TECHNIQUES ACE/Hard ACE/Soft Print samples were collected from each trial and analyzed with a reflection densitometer. Solid ink density (SID) was determined from the average of five separate measurements. Printed tone density—1 percent, 5 percent, 10 percent, 25 percent, 30 percent, 50 percent, 75 percent, and 90 percent—was determined from the appropriate targets in each repeat. Five repeats from each trial were measured and the results from these repeats were averaged to get the best estimate. Printed dot area was calculated from density measurements using the Murray-Davies equation. Print contrast was calculated from the densities of the 75 percent tone patch and the average solid ink density (SID) using the appropriate equation. BASIC—SID The type of plate had no significant effect on SID; however, the type of sleeve used produced significant differences in SID (see Figure 1). The highest SID was delivered by sleeve No. 2 or sleeve No. 3, which were equivalent. The lowest SID was delivered by sleeve No. 1. There were no interactions between plate and sleeve. Sleeve type was the controlling factor. FIGURE 4. Effect of plate type on 10 percent highlights. FIGURE 1. Effect of plate type on solid ink density. ACE/Medium FIGURE 2. Effect of plate type on 1 percent highlights. FIGURE 3. Effect of plate type on 5 percent highlights. FIGURE 5. Effect of plate type on 25 percent midtones. HIGHLIGHT TONES In the 1 percent, 5 percent and 10 percent range, plate type and sleeve type were significant in their effect on the results. There was also an interaction between plate and sleeve which influ- enced the results. Overall, plate type ACE D and sleeve cushion No. 3 uniformly showed less dot gain. These combinations are shown in Figures 2, 3 and 4. MID TONES In the 25 percent and 50 percent region, plate type and sleeve type were significant in their effect on the results. There was also an interaction between plate and sleeve which influ- enced the results. Overall, plate type ACE D and sleeve cushion No. 3 uniformly showed less dot gain. These combinations are 30 FLEXO JANUARY 2009 www. f le xography. org FIGURE 6. Effect of plate type on 50 percent midtones.
End of Year 2008