Applied patinaĪrtists and metalworkers often deliberately add patinas as a part of the original design and decoration of art and furniture, or to simulate antiquity in newly-made objects. Even a lasting gold colour is possible with copper-alloy cladding, for example Colston Hall in Bristol, or the Novotel at Paddington Central, London. brass or bronze, will weather differently than 'pure' copper cladding. For example, a new copper facade in central London will most likely not develop a 'typical' green patina until after 50 years.įacade cladding ( copper cladding) with alloys of copper, e.g. Buildings in coastal / marine locations will weather and develop a patina layer faster than ones in inland areas. A copper roof will patinate faster than a copper facade, due to the longer dwell time of water on the surface. The Statue of Liberty gets its green color from the natural patina formed on its copper surface.Ī patina layer takes many years to develop under natural weathering.

The patina protects the firearm from more damaging rust that would occur were the patina to be polished off. Firearms in this state are generally considered more valuable than ones that have been re-blued or parkerized. Often, antique and well used firearms will develop a patina on the steel after the bluing, parkerizing, or other finish has worn. It can form on pure copper objects as well as alloys which contain copper, such as bronze or brass. One example of a patina is a green surface texture created by slow chemical alteration of copper, producing a basic carbonate. Such a verdigris is water-soluble and will not last on the outside of a building like a 'true' patina. Verdigris can be produced on copper by the application of vinegar ( acetic acid). Atacamite is another name for the patina compounds.

The green patina that forms naturally on copper and bronze, sometimes called verdigris, usually consists of a mixture of chlorides, sulphides and carbonates ( copper carbonate, copper chloride or copper sulphide). The chemical process by which a patina forms is called patination, and a work of art coated by a patina is said to be patinated. Figuratively, patina can refer to any fading, darkening or other signs of age, which are felt to be natural or unavoidable (or both). The word 'patina' comes from the Latin for 'shallow dish'. Brass is also resistant to corrosion, but it is, in the long run, not as attractive since local pitting shows against the shiny background. This natural patina is solid and seldom shows a tendency to flake. One reason bronze is so highly valued in statuary is that its patina protects or passivates it against further corrosion. Patinas are restricted to exposed surfaces and are fragile (that is, they can flake off).

Patina synonym