PURPOSE: To improve working environment by incorporating a copolymer essentially consisting of poly-N-isopropyl acrylamide or N-isopropyl acrylamide as an essentially component into the above resist ink.
CONSTITUTION: The copolymer essentially consisting of the poly-N-isopropyl acrylamide or N-isopropyl acrylamide is used. Namely, the resist ink contg. the poly-N-isopropyl acrylamide or N-isoropyl acrylamide as the essential compo nent is applicable in the form of an aq. soln. on a substrate at the temp. below the temp. at which the ink exhibits a water-soluble/water-insoluble change. The excess resist ink can be removed without adversely affecting substrates, etc., by subjecting the substrates, etc., to processing, such as etching and plating, at the time. above the temp. at which the ink exhibits the water-soluble/water- insoluble change, then washing away the excess ink with water below the temp. at which the ink exhibits the water-soluble/water-insoluble change. All the processes are executable in a water system in this way and the environmental pollution by discharge and water draining is lessened.