An ink-based digital printing dampening fluid delivery system useful for printing with an ink-based digital printing system, the ink-based digital printing system having an imaging member is provided. The dampening fluid delivery system includes a supply chamber, a supply channel and a particularly-configured vapor mixing chamber. The vapor mixing chamber is in fluid communication with the supply chamber. The vapor mixing chamber interfaces with the supply chamber by way of a plurality of equally spaced, angled, small-diameter vapor exit ports for providing dampening fluid to be entrained in a flow of air provided to carry a uniform mass fraction distribution of the dampening fluid to be deposited on a reimageable surface of the imaging member.