I got curious about which inks were prone to fading, primarily through photo-degradation, but photo-degradation is also a decent stand-in for other forms of ink degradation.
On April 30th, last year, I took a bunch of pens of varying quality and made test strips. I then put them in my poorly insulated windowsill, where they’d be exposed to light, and varying levels of humidity. I thought people on the BBS might be curious enough about it to want to know the results, seeing as how often @frauenfelder makes pen posts.
All of these degrade in some way or another, but some are clearly superior, and the cost of the pen doesn’t seem to be all that related to durability.Obviously, if you want markings that last, use pencil, as I did to number the test rectangles on the bottom left. I was really suprised at how poorly the Lamy ink (fountain pen ink) fared, and how well the Pentel Flair (cheap felt-tip) ink held up.
Other survivors from a previous test:
Uni 1.0 Jetstream.
Other Complete failures:
Cheapie Bic Ballpoint.
Pentel Inkjoy. (I tested this twice without realizing- didn’t test the gel pen version.)