In order, we have:

• Diamine Grey. Slightly water-resistant, in that it is visible afterwards and almost readable, but not pretty.

• Sailor Sei-Boku – the greenish blue “nanocarbon” Sailor ink. As befits an ink by a company called “Sailor” this ink remains identical no matter how much it is dunked into water. Sei-Boku is termed “archival quality” so really should be able to cope with being dunked in a sink.

• Waterman South Seas Blue, which is really a turquoise. Here we see the difference between a sailor and the sea. South Seas Blue, when exposed to water, is overjoyed and leaps off the page in ecstasy, to join its brother and sister molecules.

• A black Sharpie marker which I happened to have lying around. No nonsense here. Water? Why should it care about water? Try bleach or napalm to erase this sort of thing.

• Diamine Monaco Red which surprised me a little (though Diamine inks are not noted for water resistance generally). Monaco Red just vanishes with barely a trace. I’ll grant that that example of Monaco Red was likely contaminated with a lot of J Herbin Rouge Caroubier, since it normally dries to a brownish “there’s been a murder sir” colour, but even so… evidence has been eradicated.

• And then I had run out of inked pens so decided to try a pencil, specifically a 3B lead in a Caran d’Ache clutch pencil. Pencils have something of a reputation (in my mind anyway) for being impermanent, given that they can be erased with a piece of rubber, but graphite particles embedded into the surface layer of paper are apparently entirely non-bothered by the presence of water.