Scientific American 36, 26.5.1849
Mr. George W. Pratt, of this city has recently secured a patent for England for his improved mode of manufacturing Printing Ink. The invention consists in employing the oil obtained in the distillation of rosin. He uses at the rate of 1 lb. rosin oil, 13 oz if rosin and 5 oz, of yellow soap, melting them thoroughly in a pot over a fire. He uses more rosin if he wants it stiff, or less when it is wanted more fluid. He then suffers this to get cold, and grinds it up with lamp black, or other coloring pigments for variously colored Inks.