Verdigris is a bluish green pigment. It was the most vibrant and primary green pigment until around the 18th century. The term is of French origin. This pigment is made by applying acetic acid to copper plates. Verdigris is the bluish-green patina that is naturally formed when metals such as brass, bronze, or copper is exposed to air or sea water for a considerable amount of time. Greek artists use Verdigris as the principal green color in their paintings. We can also see roof tops of churches and capitol buildings coated with verdigris. Artists often use this color when they want to give a sea foam look to their painting.