Photoresists of the invention contain an added acid reaction component together with one or more resins and a photoactive component. Preferred photoresists of the invention can provide processes substrates such as microelectronic wafers with desired iso-dense bias values. Particularly preferred photoresists of the invention are chemically-amplified positive-acting resists and contain an ester-based solvent such as ethyl lactate or propylene glycol methyl ether acetate in addition to the acid reaction component.