[Prestidigitweeze]

I'd love to see you play with your idea, GG. No one else -- certainly not any major publisher -- would bother to try it in epub format. Neither would most MR book creators (though Pynch veers close with his painstakingly faded covers, his CSS is remarkably clean).

I applaud you for wanting to try something new (by which I mean old). If I know you, you'd offer your books in both formats anyway -- ultimate vintage and old-fashioned but modern -- which means that everyone would win.

Even so, I voted for the latter, since that's my ultimate preference for old books. Even hoary tomes looked new at one time; besides, nonstandard formatting can be problematic. Every bookseller and device-maker seems to want to impose their own flavor of epub, which can make for unintended anomalies.

I'd love to see the result of a vintage paper background in CSS, but I have the feeling it would end up looking like the old-film-stock filters that everyone used with Avid in '90s post-production: The same pattern of pseudo-aging on every page/frame rather than anomalies throughout, as in a book/film that truly is old.

Have you ever seen a TV commercial that adds layers of flickering and scratches to what's clearly digital video? The result of your experiment could end up looking that way, too -- unless you found other ways to introduce variation and make the effect appear more organic.