Gustave Dore Artbook Pack (1860s-80s|400 pgs|archive.org/Empire)

I don't see it, and considering the provenance of the images, such an amateurish flaw seems highly unlikely.

My guess is that what you're seeing is an artefact introduced by the software you're using to view the image - the result of bad scaling or filtering. Try extracting one of the pages where you see this from the archive, and then have a look at it at full size in a plain image viewer which doesn't by default make the same kind of adjustments document viewers do. If you still see it then, please post a screenshot.

If it's me being blind and not you having jumped to faulty conclusions, I'll be happy to apologize, though. :)