Diamine Fountain Pen Ink, Woodland Green, 80 ml Each bottle contains 80 ml (approximately 2.7 fluid ounces). Diamine ink is fast drying, water based, pH neutral, and non-toxic. Diamine fountain pen inks are safe for all brands of fountain pens. These all natural dyes are light fast and have a very smooth flow. Available in a variety of vibrant colors. Diamine has been making the finest quality inks since 1864.