The present invention provides for a light-sensitive photoresist composition useful for imaging thick films, comprising a polymer which is insoluble in an aqueous alkali developer but becomes soluble prior to development, a photoacid generator which produces a strong acid upon irradiation and a photobleachable dye. The invention further provides for a process for imaging the photoresist of the present invention, especially where the thickness of the photoresist is up to 200 microns and where the process comprises a single exposure step.