An aqueous ink composition including water; an optional co-solvent; a sulfonated polyester, wherein the sulfonated polyester has a degree of sulfonation of at least about 3.5 mol percent; and an isoprene rubber. A process of digital offset printing including applying an ink composition onto a re-imageable imaging member surface at an ink take up temperature, the re-imageable imaging member having dampening fluid disposed thereon; forming an ink image; transferring the ink image from the re-imageable surface of the imaging member to a printable substrate at an ink transfer temperature; wherein the ink composition comprises water; an optional co-solvent; a sulfonated polyester having a degree of sulfonation of at least about 3.5 mol percent; and an isoprene rubber. A process including combining a sulfonated polyester resin, having a degree of sulfonation of at least about 3.5 mol percent, water, an optional co-solvent, and an isoprene rubber to form an aqueous ink composition, wherein the ink composition is substantially colorless.