A metallic plate for an electrochemical system is provided. The plate has at least one measuring structure formed in one piece with the plate. The measuring structure has at least two cuts through the plate and a first deformation of the plate arranged between the cuts. The cut edges are spaced apart from one another in sections by the first deformation so that the cut edges form at least two windows in the plate. The measuring structure has at least a second deformation of the plate. The plate is deformed by the second deformation in the region of the plate adjacent to the windows in such a manner that the windows allow light that falls on the plate orthogonally to the main plane of the plate to pass through. As described is a method of producing a metallic plate including at least one measuring structure.