When copper is exposed to atmospheric conditions it starts to oxidise. Different air agents, combined with the chemical properties of surrounding materials, even the oil from human hands, impact how and where oxidisation occurs. Copper never ages evenly and unpredictable surface patterns are part of the material’s charm.

To quicken the material’s ageing process, or attempt controlled and even surface ageing, copper can be pre-treated, provoking advanced oxidisation. One common method is salt spraying.