C is a group that is free of any hydroxy, carboxy or other aqueous base-solubilizing groups or any photoacid-labile moieties, e.g. C is suitably a C1-20 alkyl group (including cycloalkyl) that is free of any hydroxy, carboxy or photoacid-labile moieties, or a phenyl or other carbocyclic aryl group that is free of any hydroxy, carboxy or photoacid-labile moieties;