[en] Photochemical production of multi wire electrode frames for spark and proportional chambers has been proposed. In order to eliminate an effect coarsed by the incorrect bar pitch at the lead soldering points, bars are made extended an extra length provided and arranged at a constant angle or in a fan-shaped manner to a direction of electrode wires. After a negative is produced, the bars are brought to required adjustment by shortening; thus the proper pitch is obtained. The adjustment is performed by covering extra portions of bars on a negative with a nontransparent screen, or by removing the extra portions by mechanical or chemical means