Diamine Writing Ink is a water based non waterproof ink. It is perfect for fountain pens and absolutely ideal as a calligraphy starter ink. Colors can be diluted or blended to give a multitude of effects. The elegant Italian glassware bottle size is 80ml instead of the more common 30ml or 50ml bottles. A secret ingredient has been added to de-stress the surface tension of the paper which enables the ink to glide over. A combination has been achieved of vibrance in color with an even ink flow. It is recommended for vintage pens. The ink is non-toxic and free flowing.