My guess is: regular graphite pencil on porous paper is best. Any ideas about further things I have to take into account?
Pencil definitely lasts if the paper is undisturbed. I have some paperwork that's 100+ years old and with legible pencil text. On the flip side, if the paper is handled a lot, the writing will gradually fade because graphite particles just sit on the surface and can flake off.
On some level, the medium is your main problem. Low-grade paper, especially if stored in suboptimal conditions (hot attic, moist crawlspace, etc), may start falling apart in 20 years or less. Thick, acid-free stock stored under controlled conditions can survive hundreds of years.
Acid-free paper sounds like the way to go. Do you have experience with this? Or is it common knowledge? Just curious!
I also read letters from my grandparents, stored by my parents in a simple shoe box. No special conditions, just light-free and inside the home for decades. They were still very much readable. I did not pay enough attention, but I guess it was blue ink from back in the day that they used.
I collect vintage stuff that sometimes comes with paperwork, usually after spending a decade or two stashed away in the attic.
Do you just use regular graphite pencils, like with the HB scale or something?
It is easy to find either roller pens or ink for fountain pens that are pigment-based, lightfast and waterproof. It is very easy to test yourself that with such ink water has no effect whatsoever over the written text (after a minute or so of drying after writing). For example, there are many kinds of Uni-Ball roller pens with waterproof ink, but there also many other brands with similar products. (Only fountain pens, roller pens and gel pens may have pigment-based ink, the paste ink used by ball-point pens is easily washed by alcohol or other organic solvents.)
In my experience with graphite on paper, it is a much worse choice, because the writing will fade over the years, due to the rubbing of the paper sheets from each other.
The pigment-based black inks also use carbon, like graphite pencils, but any ink contains not only a pigment, but also a glue that binds the pigment to the paper, so it will not be rubbed out by touching it.
There are at least 4 dangers for a written text: mechanical rubbing, fading due to light, water and organic solvents (e.g. alcohol).
There are many pigment-based inks that are specified to be lightfast and resistant to water and organic solvents, according to various archiving standards. Such inks are available for fountain pens or they are used in certain kinds of roller pens.
If you use such inks on paper that is somewhat porous, they will also be resistant to rubbing. There are certain kinds of "permanent pens", which have excellent resistance to rubbing even when you write on surfaces like plastic, glass or metal, not only on glossy paper, and which may also be lightfast and waterproof, but the text written with such permanent pens is easily washed with alcohol or other organic solvents (like also for text written with ball-point pens).
So the answer depends on your goal, but usually what you want is either a roller pen or ink for a fountain pen that are clearly specified as being pigment-based, lightfast and waterproof, together with paper on which you have checked that rubbing does not remove the written text. When using fountain pens, one must check that the archival pigment-based ink is known to be compatible with the model of fountain pen, otherwise clogging may occur. (For example, I use pigment-based ink cartridges from Sailor Japan, seiboku or souboku, with Sailor fountain pens, so compatibility is guaranteed.)
While graphite-based pencils produce writing that is lightfast and resistant to solvents, in my experience the inherent rubbing of the sheets of paper when you handle the notebook, or whatever you had used for writing, leads over the years to a fading of the text, so I do not like this method.
No no no no no!
Archival data should never be made on intrinsically valuable material; doing so makes it subject to theft or re-use for something "better".
Example: There is a reason why more marble statues survive from antiquity than bronze statues.... Bronze has an intrinsic value (theft) and future artists would also melt down existing bronze statues to make something "better".
The engraving pen on glass is a good one. Any experience with it?
https://www.diamineinks.co.uk/products/diamine-30ml-archival...
> Waterproof archival quality fountain pen ink in Blue-Black. Initially writes Blue, then oxidises to Black over time as it bonds to the paper. Traditionally used to record births, deaths & marriages.
And from another source :-
> Permanent archival blue-black ink based on an iron-gall formulation, as used by registrars and the clergy for official documents.
> Iron gall ink formulations have been used for around 1,500 years, and many of the world's most historic documents have been written using it. This ink will remain legible for hundreds of years.
> Please Note: This is an iron-gall ink, which contains particles that can clog fountain pen feeds. It's also acidic, which can damage steel nibs. Use with caution, and at your own risk. Not for use in valuable pens.