With the patina, the piece is given its final appearance. Depending on individual preferences, the patina desired can vary to a great extent and substantially alter the expression of the work. Even when the work is left as a raw casting, traces of the processing of the original surface have to be approximated with a partial patination.

During patination, the color of the metal is manipulated by means of oxidation and de-oxidation. In complex procedures, chemical reactions on the surface of the casting are triggered using heat along with metal salts, alkaline solutions, or acids. For the most part, copper nitrate, iron nitrate, silver nitrate, potassium polysulfide (sulfurated potash), and hydrogen peroxide are used.

The color that results is influenced not only by the concentration of the chemicals, but also by temperature, the method of application, and the metal being patinated.

The result can be varied by spraying, dipping, application with a brush, sponge, or soft cloth. The intensity of the color can also be influenced by intermediate brushing or polishing.

Experience gained in a process of trial and error makes it possible to achieve a suitable patina.

The patina can also be given a conserving application of wax, which makes the sculpture seem darker and deeper. The greenish-black patina of the Broderbrunnen was created to correspond with the one-hundred-year-old original.

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