Modern printing inks are made with oils or petroleum distillates combined with organic pigments. Black ink is made with carbon nanotubes. More traditional inks are made with a mixture of dye and oil or water.
The earliest known inks in China, India and Egypt were made from plant dyes and ground minerals such as graphite. Inks have also been taken from cephalopods such as squid and cuttlefish. Animal glue and gum arabic were also often used as binding agents. Many different cultures came to the discovery of ink independently and there is a wide variety of unique formulas for it.
Modern inks can be roughly divided into those used with printers and those used for writing. Color printing inks are frequently made of linseed or soybean oil with natural pigments made up of salts containing dyes. These inks may also use a heavy petroleum distillate for the solvent in place of oils. Carbon nanotubes are used for black ink in printers as they can be expelled without clogging the nozzle.
Pens for writing traditionally used a mixture of water and dye, but modern pens now use an oil-based system that resembles a soft paste. These inks dry more quickly and have less of a tendency to smear.