Formylated Novolacs were prepared by the reaction of Novolacs with formic acid-acetic anhydride in the presence of pyridine in tetrahydrofuran at room temperature. When the resulting formylated Novolacs films were exposed to deep-ultra-violet light, photochemical decomposition of the formyl group was observed. This reaction generates Novolacs through decarbonylation of the formyl radical, which is formed in the first stage of the photo-Fries rearrangement. More than 50% of the formyl groups decomposed after an exposure of approximately 500 mJ cm-2. Both negative and positive tone images can be manufactured by developing these films with a suitable solvent.