To estimate a hardener concentration in an original copper sulfate-plating bath in which a copper plated film is formed while producing a photogravure without producing a copper-plated film for physical property evaluation which is not counted among production, and particularly to provide a method for controlling the copper sulfate-plating bath to control the concentration of a hardener to be added to the plating bath in order to stably produce the copper-plated film suitable for mechanical carving and ballade peeling, particularly in the production process of the photogravure.

The method for estimating a hardener concentration in the copper sulfate-plating bath includes peeling a copper ballade from a cylinder after mechanical carving, and performing the scratch test of a copper-plated film surface.