Description 30ml glass bottle of Diamine Registrar's Blue Black Ink. Archival and water resistant permanent ink for document signing. Diamine Registrar's Blue Black fountain pen ink is a deep shade of blue-black that leans towards black. Having trouble deciding between colors? Use our Ink Comparison Tool to quickly and easily view different colors side by side.We offer Free Shipping on all orders over $50 for US customers, and for orders over $250 for our Canadian customers.