These inks were transparent, but once applied to the parchment, the slow chemical reaction between acid and salt left a suitable dark residue that penetrates the paper, leaving permanent markings. Unfortunately, if the mix was wrong, the ink would contain too much free acid which could eat up quills, but far worse could leave holes in the manuscript. 9th century CE Romanesque miniscule calligraphy, from the Alcuin Bible. These inks could be made in an unprecedented array of colors, and were much less corrosive to pens and paper. Other additives may be used to help the wetting and stability of the ink, or to prevent the accumulation of solid dyes on the inside of the pen.
Some manufacturers offer grays, purples, oranges, and other color variations.
It did not take long after the development of the offset printing press for printers' inks to become the most significant segment of the industry. These inks are more greasy and gelatinous than writing inks, and are carefully calibrated to provide the best mechanical performance in specific kinds of printing equipment. 1890 advertisement for Pelikan paints by Julius Diaz. As a mid-1800s German firm, Pelikan would probably have been one of the first firms to make inks based on aniline dyes. The gluey, non-Newtonian nature of printers' ink was the inspriation for the ink used in Biro's original ballpoint pen.