Organic substances (monomeric or polymeric) which are sensitive to light. There are two types of photoresists: positive and negative. Positive photoresists are often polymeric material which have photolabile groups which cause the material to become soluble in the developer on exposure to light. Negative photoresists are often monomeric material which polymerize on exposure to light.

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A light sensitive material used in several industrial processes, such as photolithography and photoengraving to form a patterned coating on a surface. Photoresists are classified into two groups, positive resists, in which the exposed areas become more soluble in specific chemical solutions (resist developers) and are removed in the developing process, and negative resists, in which only the exposed areas become resistant to the developer, so the unexposed areas are removed during the developing process.

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A substance that becomes soluble when exposed to light

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