Ink-jet ink sets, pigment-based ink formulations, methods of printing, and methods of enhancing print quality, are disclosed. One exemplary ink-jet ink set, among others, includes a pigment-based ink formulation at a first pH, including: a pigment-based ink, and an amphoteric dispersant having an isoelectric...http://www.google.com.au/patents/US8052786?utm_source=gb-gplus-sharePatent US8052786 - Amphoteric pigment dispersion containing ink formulations, methods of using ink formulations, and systems using ink formulations
