Waterman Serenity Blue is one of those inks with a reputation. It’s well known for being one of the safest inks there is, recommended for use in the most delicate of vintage pens.
As far as its colour goes, it’s a nice royal blue, which isn’t to my taste (reminds me too much of school).
Here I am doodling the Inkling.
You can find some more reviews of Waterman Serenity Blue on Pennaquod.