Diamine - Archival Registrar's Ink
Diamine Registrar's Ink has been used for many years by a large number of UK registrars for official permanent records. ~ This waterproof blue-black archival ink is a traditional iron-gall formulation and is suitable for use in all fountain pens. It will last many hundreds of years on the page. Registrar's Ink will initially write blue, then darken* Due to the acidic nature of the iron-gall formulation it is recommended that pens are flushed through after use as a precaution against corrosion.