PURPOSE: To obtain a high precision filter by providing transparent electrodes which correspond to plural picture elements in ≥2 colors on the surface of a base body, forming a coloring layer which contains a hydrophilic binder on each transparent electrode layer, and coloring them successively and electrolytically in a developer which contains couplers and the base for color processing with the couplers in the developer.

CONSTITUTION: After photoresist 22 is formed on the projective layer 20 of phosphorus silicate, etc., of a solid-state image pickup element 10 formed by provding an insulating layer 14, electrodes 16 which correspond to three color picture elements for, for example, red R, green G, and blue B, an electrode 18 for external connection, and the protective layer 20 on a glass base or a substrate 12 in the order, a prescribed pattern is obtained through exposure and development by using the mask of the photoresist, and then the insulating layer is provided without the contacting of an intersection part 34 and a transparent conductor 32 is vapor- deposited, thus forming transparent electrode patterns R, G, and B, connection terminals 26R, 26G and 26B, and lead wires 28R, 28G, and 28B. A coloring layer 100 which contains a hydrophilic binder (gelatin, etc.) is formed over the entire surface, and the layer 100 is impregnated with a coupler 48 and the base for color processing with couplers in a developer 54 which contains couplers 48 and the base for every color to color by electrolytic oxidation. Thus, a high-precision tricolor filter for red 48R, green 48G and blue 48B is formed.