Outstanding acid-free ink is archival quality, waterproof, waterbased, has no odour, will not smear nor feather when dry and will not bleed through most papers. Use for graphic art, sketching, pen and ink illustrations, awards, freehand art, calligraphy, as well as general letter writing and legal documents. AP non-toxic. Pigma ink, invented by Sakura over 25 years ago, continues to be the most reliable permanent ink on the market today. In the early ’80s, Sakura’s labs identified the need for an inexpensive drafting tool that used superior pigment-based ink instead of low-grade dye inks. The breakthrough came with the discovery of how to reduce the pigment particles to submicron size so that the ink flows evenly through the narrowest of pen nibs. Pigma easily outlasts and out-performs inks made by competitors who have tried to duplicate Sakura's ink technology. Having such a long history with this specialized ink, Sakura has been able to constantly improve on their formula resulting in the smoothest flow, the most pleasant colours, stable pigments, and practical writing instruments. Pigma has become the standard for what is defined as permanent ink, relied upon by those whose jobs depend on marks and notations that stand the test of time. The properties of Pigma ink create magic on paper for millions of users. This permanent, fade-resistant, chemically stable, pigment-based ink will not bleed or run if liquids are spilt on or applied to the document after the ink has dried. Use Pigma Micron to leave a mark that will last a lifetime.