I've missed this conversation by some days, but feel that I should add my voice. I am not in agreement with many of you, I will warn you up front.
My feeling is that the comics we hold in our hands came from artists, but passed through the hands of somebody in the production process who may or may not have had much care about the quality of end product as much as they should, the printer. Depending on the publisher, the issue, or even the copy of the book, there might be mis-registrations, poor attention to ink levels or pressure on the plates (resulting in smears, blobs, or worse), crap on the plates preventing defects in color fields, paper trims out of square or askew, etc. Many of these defects obscure the art, particularly the mis-registration of the plates in detailed areas of the drawings.
Say what you like about the pure art of preservation of cultural artifacts. I understand those arguments. If a sloppy printer screwed up a nice page of comic art, and I can do something about it, I chose to do it. My releases are, after all, just scans...not originals. They aren't precious. That differentiation took place the second the book hit the scanner, however much or little 'editing' I do. All scans are copies, differing in exposure and color balance from the source.
In my way of thinking, I am trying to make the page look as much as it can as if the book were well printed and well preserved. Some of you will shudder to read this. I felt that this is worth stating, however, so that you didn't mistake my silence for agreement on this issue.