A method of marking is disclosed in which a propellant stream is passed through a channel and directed toward a substrate. Liquid marking material, such as ink, is controllably introduced into the propellant stream and imparted with sufficient kinetic energy thereby to be made incident upon a substrate. A multiplicity of channels for directing the propellant and marking material allow for high throughput, high resolution marking. Multiple marking materials may be introduced into the channel and mixed therein prior to being made incident on the substrate, or mixed or superimposed on the substrate without registration. One example is a single-pass, full-color printer.