What is ink?
Inks were invented by the Chinese about 4500 years ago. These consisted of a liquid base and pigments. When the liquid base dried the pigments remained on the material as residue. The Chinese used a mixture of soot, gelatin and lamp oil. They also added some musk to remove the odor of the oil. With the advent of paper, new types of inks were invented. These included metal dyes, seed husk and cuttlefish. About 1600 years ago the ink quality improved with the use of iron salts, tannin (from trees) and some thickener. The ink color used to be Blue-black in shade. The color used to change over a period of time to brown.
Real advancement of inks came about with the printing technology and today, the modern inks are a mixture of complex fluids, solvents, pigments and resins as well as lubricants. The advent of writing pens also changed the composition of the ink. Solid inks had been manufactured by the Chinese about 2500 years back. Today, a ball point pen has a non flowing synthetic ink that flows out by application of pressure.