Abstract: The present invention provides improved dye based ink solutions for use in ink jet printing. In one embodiment of the invention, an aqueous ink with improved water solubility and waterfastness is provided that includes a dye component and a hydroxyethylated polyethylene imine polymer, wherein the hydroxyethylated polyethylene imine polymer has incorporated therein approximately 10 to 55 percent hydroxyethyl groups by weight. Alternative embodiments of the invention include the use of hydroxypropylated polyethylene imine polymers or epichlorohydrin-modified polyethylene imine polymers. In addition, aprotic solvents such as dimethyl sulfoxide and tetramethylene sulfone may be added to improve the solubility and stability of the dye solution, and humectants such as 2-pyrrolidone may be added. According to the methods of the invention, an ink with improved stability, jetting characteristics, solubility and waterfastness may be provided.