and I went fishing a few months ago for images to print onto 8″x8″ squares and it's clear that older objects pick up damage over time. There are all kinds of beautiful objects from ancient Egypt but they are not made of paper. A print from the 15ᵗʰ century looks like
but paintings like that get a lot of attention in the form of cleaning and retouching.
Many of my favorite images come from paintings that are about 100 years old, such as the Futurists. These are old enough to have scans in the public domain but young enough that they haven't picked up the damage you see in older art that hasn't been heavily retouched.
Yeah of course, the og medium probably won't last 500 years, but if it's good enough to matter people will put them in safe spaces or reproduce them. Good quality modern books kept in ok storage conditions should last hundreds of years. I have a couple ~100 years old books and they look as new besides slight yellowing.
Prints are different since they're much more exposed and fragile than books
Anything that is on display is going to fade more quickly because of light than something that is kept closed.
When I was a kid in the 1980s I collected many mass market paperbacks (expected to be ephemeral) from as far back in the 1960s, even in the early 2000s I thought these held up pretty well, but circa 2020 I think many of them are getting pretty bad. (Contrast that to trade paperbacks that are sometimes "acid-free" but that frequently break in the first minutes of use because of incorrect and inconsistent construction.)
My house is humid and not a great place to store books, but I went looking in an academic library that follows "good" practices and found that mass market paperbacks from the 1980s and earlier were in bad shape too.
The collection of the Metropolitan Museum has an API
https://metmuseum.github.io/
and I went fishing a few months ago for images to print onto 8″x8″ squares and it's clear that older objects pick up damage over time. There are all kinds of beautiful objects from ancient Egypt but they are not made of paper. A print from the 15ᵗʰ century looks like
https://www.metmuseum.org/art/collection/search/367024
It's frequently said that oil paintings hold up well over time such as
https://www.metmuseum.org/art/collection/search/816514
but paintings like that get a lot of attention in the form of cleaning and retouching.
Many of my favorite images come from paintings that are about 100 years old, such as the Futurists. These are old enough to have scans in the public domain but young enough that they haven't picked up the damage you see in older art that hasn't been heavily retouched.