Waterman Standard Long Ink Cartridges for Fountain Pens, Serenity Blue, 8-Count

Waterman Serenity Blue isn't waterproof, which can be a plus I guess with spills. I would certainly let my kids use it, but the Pilot Namiki standard ink black or blue is extremely waterproof. If you are a college student this would be a big plus, the Pilot ink. I would go back-and-forth between these two inks, both are excellent, I certainly would use the Pilot ink on checks, signed documents. But then again, I'm not an ink nut, nor have to rotate pens out like some people seem to do with beer, I find what I like, that's it. The only guilty pleasure ink I buy is Private Reserve Chocolate, it's lovely brown and can be used in place of black. It's semi waterproof to me as it is a dye ink, the writing will fade but stay legible, the stain created and letters will turn a pinkish red, a good indication that it either got wet or somebody tampered with it. Waterman Serenity Blue, used to be called Florida something or other, is a very pretty what I would call Academic blue, it isn't a bit waterproof, but ink feathering and bleed through is minimum on cheap paper. I would use a Chinese or European fine nib or a Japanese medium with this ink on cheaper to help it behave. You can't go wrong with this ink.