Abstract: A method of preventing clogging of nozzles, particularly nozzle orifices in a drop-on-demand ink jet printers, during intervals when no ink flows through the nozzles, e.g. during non-printing intervals, when using an ink composition intended for recording permanent information on essentially non-absorbent surfaces. The ink composition is made up of a solvent, a non- or low-volatile fraction and a colorant. The relative quantities and solubility of the constituents are selected such that when printing terminates and a portion of the solvent evaporates at the nozzle orifice, a concentration of colorant and less volatile fraction builds up in the region of the nozzle orifice. This causes the colorant to migrate to an environment in which its affinity is greater, i.e. further within the nozzle.