Mr. CClyde, how's your progress on dot gain problem?
I've decided the best course is to take the time to document the set up on one unit from scratch.
The press operators have been setting up by the math where each spec is taken as true according to supplier's spec sheets. This doesn't take into account wear on the bearers, over-under spec on plate packing, blanket thickness, paper, roller dia. etc.
So I'm scheduling a full set up including micrometer readings on everything. Then we'll do a dry break away and record a value for the zero point.
Then we'll tackle the water amount and emulsification.
I've seen a consistent over-emulsification on long runs and after an equivalent series of short run jobs.
I think (hypothesis) what's happening is a snowball effect caused by increased pressures and too much water.
The increased pressures are small enough that they're not obvious on the blanket or sheet, but they cause the water take-up to increase more than normal with each impression. This with the elevated water results in a gradual transfer of micro drops of ink into the water and water into the ink. The initial transfer may be any one of number of contact points, but once it begins it transfers through the whole ink train and back through the water. By the time the press operator sees the effect it's too late. He assumes it's the plate not clearing (it is impossible to see the actual mechanics without the scope) so he chases it with more water to clear the plate, that drops his SID and the snowball is now in free-fall down the mountain.
I'll post the results on the first unit when we're done.