We run under blankets on both our 40" and 26" Komori's and I reckon we get a fair amount of dot gain as a result. I haven't got the tools at work to measure the gain, but I've noticed that on higher quality jobs that half tones are hard to get spot on often requiring what I'd consider a fairly low density to match proofs. However, if you're running an image that requires a good solid with a reversed out picture or solids/screens in line from grip to tail a fair amount of compromise is necessary: ie, either the solid or the picture is never *quite* perfect.
Irritating to say the least, and unnecessarily time consuming....
A quick comparison between a printed screen and an unused plate (same image) shows pretty high gain, I'd ballpark it at 10/15% but again this is just guesswork given the lack of proper tools to actually measure it, but my denso tells me it's not overloaded with ink.
I also think that the ink we run is a contributing factor. For reasons that neither the rep nor my boss will disclose, we run Hostmann Steinberg "Perfexion" on a non-perfecting press, seems a little light to me and plenty is required for proper density.
I guess the benefits of a soft under packing outweigh the cons in our case however, as we generally run campaign work that involves huge run numbers and you get away with minor bingles as the softer blanket/packing combo seems pretty resilient. For example the run we are currently printing has got to be 500k+ impressions.... Plenty of bloody ink too lol using roughly 2kgs/deck/stack..... sigh....
