For true archival purposes, even printing is somewhat less secure than might be assumed.

Possibly the best "archive" prints are those from laser printers, since the ink is heat-fused to the paper, and the black ink fades very little. I don't have experience with whether color laser prints retain color fidelity over long times. I would expect it to be fairly good, but haven't seen much comment, and even with the best color laser printers available now the initial color fidelity is a bit inferior to other methods.

Laser prints, however, when stored for long periods, even under good temperature/humidity conditions, do have a tendency to "fuse to each other" and I have recently gone through some records from ca. 1990 for which separating the pages of "laser" prints requires rather "delicate" handling. The printers of that era used fairly heavy ink applications, and newer printers that use finer inking may be less prone to this problem.

Ink jet printer makers claim long life for their prints, but the claims resemble quite closely the claims by writeable CD makers, and can't really be taken too seriously. For almost all available inks I've seen, fading is very rapid with any exposure to sunlight, and must be assumed to occur even in low light. Nearly all inkjet prints will "run" if exposed to even slight moisture, and images get fuzzy even in normal living area humidities.

"Waterproof" prints can be made on any inkjet printer by using one of the special "papers" available (Amazon Adventure Paper is the one most easily available in the US?) but the paper runs near 50 cents (US) per sheet for A size (8.5 x 11 inch) and about $1.25 per sheet for B (11 x 17 inch). Fading still happens with the waterproof prints.

Even fairly cheap "office grade" papers commonly sold here usually are reasonably close to "acid free" but you have to verify that quality to avoid fairly rapid embrittlement and crumbling for anything you intend to store for more than a year or two. (I have some horrible examples from ca 1994 and before.) Even being acid free, so that the ink color isn't destroyed, doesn't assure that the background page won't "yellow," which is almost as bad when you try to re-archive things that need it.

Hand writing using ferrous ink on animal skin or papyrus parchments has a reasonably verified longevity, if you're willing to make your own ink and parchment; but even for these meda the storage conditions best suited to long storage time are somewhat difficult to produce and ensure without personal ownership of a few very large sand dunes in a desert climate ... .

John