How pastel pigments work – and why they remain stable for centuries

Pastel is one of the most durable painting mediums because it is almost pure pigment. Unlike oils or acrylics, it contains no liquid binder that can yellow, crack or chemically react over time. Stability is built into the material itself.

What pastel is made of

Pastel sticks consist of finely ground pigment with a minimal binder. The binder only holds the particles together; it does not form a film. Because of this, the color you see is the pigment in its natural, unaltered state.

Why pastel stays stable

• No chemical aging: No oils or polymers that can oxidize or darken.

• Lightfast pigments: Professional-grade pigments retain their color for decades.

• No cracking: There is no paint film that can break or become brittle.

• Minimal material stress: Dry pigment does not shrink or expand.

Most changes in pastel artworks come from external factors — pressure, humidity, poor framing — not from the medium itself.

What collectors should know

With proper framing and protection from mechanical damage, pastel works remain visually unchanged for generations. Museum glass, a sealed backing, and stable room conditions are usually enough. Compared to other mediums, the conservation demands are low and predictable.

Why this matters for value

Material stability is a key factor for long-term collecting. Pastel offers the rare combination of purity, permanence, and minimal risk of degradation — which makes it a reliable medium for serious collectors.