The Diamine Oxford Blue Ink Bottle - 80ml. From the year of 1864 Diamine Co. has been providing immense range of fountain pen inks, Calligraphy/ Drawing Ink & Stamp Pads and able to sustain till now by producing fine quality ink with traditional method. Diamine Ink is water based ink that has been the foremost preference for many pen lovers. The excellent quality of ink goes along with all kind of brands. It is perfect for fountain pens and absolutely ideal as a calligraphy starter ink.