Oxidation

Oxidation is a chemical reaction in which a material changes because it combines with oxygen or loses electrons. In art materials, it often refers to how oils, pigments, or metals change over time when exposed to air.

1. Oxidation is a chemical process in which a substance reacts with oxygen or undergoes a loss of electrons, causing a change in its chemical structure and properties.

   In painting and art materials, oxidation is especially important because it affects the drying and aging of materials:

   • Oil paints: drying oils such as linseed oil harden mainly through oxidation, as the oil reacts with oxygen in the air and forms a solid polymerized film.
   • Pigments: some pigments may change color or stability through oxidation or chemical reactions with the environment.
   • Metals and gold leaf: oxidation can cause corrosion or surface changes in metals, although noble metals such as gold are highly resistant.

In painting, oxidation is a fundamental process in the chemistry of oil painting. Unlike watercolor or acrylic, oil paint does not dry mainly through evaporation of water or solvents; instead, the oil binder reacts with oxygen and gradually transforms into a solid, flexible film. This process influences drying time, durability, and the long-term aging of artworks.

• Oxygen causes chemical change: oxidation occurs when a material reacts with oxygen or loses electrons.
• Oil paint dries through oxidation: drying oils absorb oxygen and form a hardened paint layer.
• Oxidation affects longevity: the process can contribute to both the stability and aging of artistic materials.
• Different materials oxidize differently: pigments, oils, and metals have different levels of chemical stability.