The present invention provides a method of lithographic patterning. The method comprises: applying to a surface to be patterned a photoresist (18) comprising a polymer resin, a photocatalyst generator which generates a catalyst on exposure to actinic radiation, and a quencher; exposing the photoresist (18) to actinic radiation through a mask pattern (12); carrying out a post-exposure bake; and then developing the photoresist (18) with a developer to remove a portion of the photoresist which has been rendered soluble in the developer. Either the polymer resin is substantially insoluble in the developer prior to exposure to actinic radiation and rendered soluble in the developer by the action of the catalyst, and by the action of the quencher during the bake, or the polymer resin is soluble in the developer prior to exposure to actinic radiation and rendered substantially insoluble in the developer by the action of the catalyst, and by the action of the quencher during the bake.