A dispersion ink for ink jet printing and which is stable and produces good quality print on plain paper for extended periods of time without the need to interrupt printing to clean the print head, comprises a diluent containing a non-polar component, a pigment and a dispersant for stabilising the dispersion of the pigment in the diluent, and has a polar solubility parameter greater than 0 but not greater than 7.0 MPa<1/2> and a dewetting velocity of at least 100 mu m.sec<-1>, measured on a surface having a surface energy of 10+/-1mN.m<-1>.
