D
Deleted member 16349
Guest
Rising,
I am glad you posted the ink data. As an example, I have used your ink 1 data.
Ink 1
Ink Requirement Print
g/m2 Density
1.17 0.96
1.37 1.04
1.46 1.10
1.66 1.16
2.05 1.24
If we look at the range of density from 1.04 to 1.16 this is
1.10 +/- 0.06 density pts.
The +/- 0.06 is just a bit more than the usual tolerance range of +/- 0.05 which one sees often as a target range for printing. It is interesting to see what the percentages of change in ink are required for that range.
Total range from 1.04 to 1.16 density points is related to the difference from 1.37 grams to 1.66 grams. Calculate the total range and we get.
(1.66 - 1.37)/1.37 x 100% = 21.17% change in ink grams from the lower end to the upper end. That is a large change in ink.
This implies that for density control, the operating window for ink is quite large.
The problem with offset presses is that they have a hard time maintaining the ink quantities even with a large window to aim at. This of course is related to the design of the press ink feed system.
Thanks for providing the ink data. It clearly shows the general problem and the solution for density control.
It also shows that if one wants to save ink, then there is much to save if one can tightly control the density in the lower half of the tolerance range.
