PURPOSE: To obtain a resist for the color filter of a solid-state image pickup element having favorable spectral characteristics especially in a blue region by introducing specified photo-cross-linkable constituent units into part of a saponified product of polyvinyl acetate having a specified degree of saponification to improve the dyeability and to retard the progress of a dark reaction.

CONSTITUTION: Photo-cross-linkable constituent units represented by formula I (where X is a group represented by formula II, CO2- or NH4+) are introduced into part of the principal chain of a saponified product of polyvinyl acetate having ≥75% degree of saponification, and the resulting product is used as a resist for the color filter of a solid-state image pickup element. An aqueous soln. of the resist is coated on the transparent support layer of a solid-state image pickup element, prebaked, patternwise exposed through a mask, and developed to form a layer to be dyed, and the layer is dyed. The progress of a dark reaction in the resist after coating is retarded, the resist has high dyeability after development, and a filter having favorable spectral characteristics especially in a blue region and high clearness is obtd.