Thus, typically the substrate has the formula: ???R???B???, where ???R??? is a color coupler moiety ??????B??? is a blocking group such as a phosphate, a sulfate, an acetate or a butyrate, or the like, linked to the color coupler moiety by an enzyme-cleavable (e.g., hydrolase-cleavable) linkage such as an ester (including a phosphate ester or a sulfate ester) linkage or an amide linkage.