WATERMAN Bottled Liquid Fountain Pen Ink, Serenity Blue, 50 ml (S0110720). Bottled ink for all WATERMAN Fountain Pens. Liquid ink produces an intense line in brilliant colors. Like the tranquil echo of a dream, Serenity Blue brings peacefulness to the page, ready to awaken pleasant thoughts. The ritual of filling ink from a bottle enhances the noble experience of using classic fountain pens.