A process of forming a resist image in a microelectronic substrate, the process comprises the steps of: (a) providing a substrate having a polymer coating thereon, wherein the polymer is insoluble in water having a pH less than or equal to a specified pH (e.g., 7.0, 6, 5, or 4); then (b) imagewise exposing the coating to radiation such that exposed and unexposed coating portions are formed, with said exposed coating portions being soluble in water having a pH less than or equal to said specified pH7.0; and then (c) contacting said coating to a developing composition comprising carbon dioxide and water, said water having a specified pH less than or equal to 7.0 (and preferably a pH of about 2 or 3 to 4, 5 or 6; i.e. a specified pH less than or equal to 6, 5, or 4), so that said exposed coating portions are preferentially removed from the substrate as compared to said unexposed coating portions to form an image thereon.