Copper patina, or patination is a term that refers to the layer that develops on the surface of copper when it is exposed to certain sulphides or oxides. These sulphides and oxides can apply naturally and over time to the copper or, they can be applied through a method known as forced patination. 

Forced patination is when one purposefully aims to change the appearance of the copper. A patina develops on copper as a level of protection from corrosion.

Due to copper creating it's own barrier against corrosion, the resulting colours and patterns are always unique and impossible to replicate - In a way, you could say the copper decides how it will look.

While it usually refers to a chemical process, a patina can also mean any aging process that causes natural discoloration or fading, including extreme temperature changes.

Some of the most colourful patinas can be created using simple household products such as salt or vinegar. Others are much more complex and require multiple processes and many days, weeks or months to achieve.

In a clean, natural environment, it can take up to 30 years to achieve the iconic green patina that copper is known for. Similar results can be achieved through controlled patination in as little as a few days, with deeper and more colourful patinas taking longer.

Because of patina's aesthetically pleasing appearance, copper and copper alloys, including brass, are often used in architectural projects.

Famous buildings that display coppers' blue-green patina include the Statue of Liberty, the Canadian Parliament Buildings in Ottawa and the NEMO Science Centre in Amsterdam.
If you want to keep learning more about patination, copper and other precious metals, head over to our Instagram @empirecopper or to our Facebook Page, Empire Copper. 
July 11, 2021 — Cameron Hayes

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