NAC-5(Naphthoquinone-1,2-diazide sulfonyl chloride), as an additive, was applied to enhance the photosensitive rate in composing a positive type of photoresist with naphthoquinone diazide derivative. Quantitative unit of energy absorption of NAC-5 based on molar weight using 365 nm optical pattern generator was measured to estimate the availability as a role of photoinitiator or an improvement agent for photochemical reaction. Comparing with the ester compound of NAC-5 with THBP(trihydroxybenzophenone) the rate of energy absorption of NAC-5 in the given range of UV light exposure was greater than that of THBP-ester of naphthoquinone diazide. Conclusively, NAC-5 was regarded as superior in photosensitivity.