Photosensitive compositions which can be developed by alkali solution, comprise (A) a polymer containing at least one carboxylic acid group in the molecule and having a molecular weight of 200,000 or less, (B) selected .alpha.-aminoalkylphenone compounds as photoinitiators and (C) an ester of a polyol, wherein the polyol is partially or fully esterified with an ethylenically unsaturated carboxylic acid a monomeric, oligomeric or polymeric compound having at least one olefinic double bond.