I am assuming (never a good idea) that you are referring to "how easy is the ink to clean from the pen".
I meant "if the ink has a propensity to stain" as well, in whichever way you meant it. The way I would think of it is that there is a continuous spectrum of possibilities, with several non-exhaustive waypoints listed below:
«easy to clean»
all traces removed simply by flushing with water at room temperature
requires prolonged soaking in some manner to be able to flush clean
requires 'scrubbing' with something, e.g. a paper towel or a cotton-tip applicator (or 'q-tip'), that is softer than the surface of the material to which ink has adhered despite prolonged soaking
(some might classify that as "staining" already, just because the pen barrel cavity is difficult to access)
colourants have chemically reacted with the surface of whatever material came into contact with the ink, and either chemical treatment (e.g. with household ammonia or commercial pen flush solution) or physical removal of the surface layer (i.e. scrubbing and/or polishing) to remove all traces of colour
no amount of chemical, physical or destructive treatment will remove all traces of colour from the ink from the material
But then, factors such as:
- how long an ink has been left in a converter, cartridge or pen's barrel cavity;
- how concentrated the ink is, or has become due to loss of volume through evaporation of water as a constituent;
- the material of the ink reservoir itself
would all come into play. Just because something would "stain" a perfectly sealed $0.06 plastic sample vial undisturbed for four weeks does not mean it'll stain a $6 converter, the barrel of a $60 eyedropper pen, or the ink window on someone's prized $600 piston-filler. If someone wants to know with any reasonable level of confidence whether an ink would stain his treasure of a 1950s vintage celluloid pen without risking the pen itself in any way, the only way is to have load the ink up in a similar pen or at least soak a piece of the same aged and rare material in a test tube of ink for several weeks.
Why would any ink reviewer do that, unless it has already happened against his/her original intentions, and he/she just want to share that unfortunate discovery at his/her expense? It's not that I want to inflict loss and/or despair upon those whose tastes in the fountain pen hobby I don't share, but if an ink doesn't ruin my $3 Wing Sung 3008 piston-filler, what do I care as an ink reviewer whether it would on the other hand stain a $300 vintage pen that cannot be replaced, given I'm not into vintage pens?
That's the basis of my inquiry. I don't use or care for vintage pens, so as an ink reviewer I certainly wouldn't test for how "safe" an ink is to use with vintage pens. As for fellow or prospective ink reviewers who love vintage fountain pens, would they really test a new ink inside their prized vintage pens just to find out, and share either good news or bad news with the rest of "the community" in the name of "the common good"?
"Better you (the ink reviewer) wear the risk/loss than I (the prospective user of that ink)" just doesn't cut it as a reasonable position to take. Neither does, "it'd cost you less than it'd cost me to find something out, so the onus is on you." That's the sorta mentality I'm staunchly against. Those who spend hundreds or thousands of dollars on vintage pens because they love it should be the one to be taking the risk in order to discover the information and share it with like-minded folk, if that is to be done at all, and not up to those who already have access to the inks, test materials, labs and what-not with supposedly less at stake to do the work.
Edited by A Smug Dill, 04 November 2019 - 03:54.