[freitzkriesler]

My family has a handwritten journal from a family member that wrote it in the 1880s. It is still in good condition.

I also have 100-150 year old books on koine greek (modern versions are trash). They're in great condition.

I'd say print. Paper, hardbound copy books stored in a proper place so they last. Next up is stone.

[wl]

The kind of paper is important. I've handled incunabula, printed books from before 1500. Maybe the paper is dirty from hundreds of years of handling, but the paper itself tends to be sturdy and supple. This continues up until the mid 1800s when new methods of paper making resulted in the presence of aluminum sulphate, which makes the paper turn brittle and yellow over time. It was sobering to see a volume of Description de l’Égypte (1809-1828) side by side with a volume of Monuments de l’Égypte et de la Nubie (1835–45). They're comparable works, elephant folios of plates illustrating Egyptian monuments. The former uses the older paper, the latter the newer paper. The newer volumes looked much older and the paper was brittle.

If you're printing something today that you want to last for hundreds of years, make sure you're using acid-free paper and archival-grade ink.

[Izkata]

> stored in a proper place

That'll probably get you a lot longer than 100 years. We still have my great-grandfather's emigration paper from somewhere around 1905, as well as other random papers from the 1920s-1930s, just stored in a shoebox.

[bregma]

My mother has a bible from 1607 in a shoebox. Maybe the shoe box is kept in a plastic bag. The previous owner, her uncle, kept it on a bookshelf.

They sure don't make them like they used to.

[wl]

Yes, they don't make them like they used to. Including that shoe box, which is not made from acid free paper and is causing that bible to degrade as we speak. I'd urge your mother to move the bible to an acid-free archival box. They're not that expensive.

[Encrypt-Keeper]

You could at least like, get a nice fire safe box for it lol.

[freitzkriesler]

Dark, dry, and away from insects is really all one can do.