For reasons of cost and weight, copper was chosen as the medium for the statue. A very new method for the time was adopted to realize of the statue: galvanoplasty, a type of electroplating, or "the art of moulding without the help of fire" was chosen over hammered copper. A scientific report of November 19, 1866 said that electrotype copper allowed an "irreproachable reproduction" and a solidity that left nothing to be desired. Only Eugène Viollet-le-Duc thought that the galvanoplasty technique would not long resist the atmospheric pollution in Marseilles.