Negative-working lithographic printing plate precursors can be imaged and then processed using a single processing solution in a processing apparatus without rinsing or gumming before the resulting lithographic printing plates are used for printing. The single processing solution (developer) comprises at least 2.5 weight % of a nonionic surfactant having an HLB value greater than 15 and at least 5 weight % of a polar organic solvent. Processing is accomplished without replenishment and reduced sludge formation is seen at the end of the processing cycle.