A reducer (or thinner) is a liquid used to thin paint to the correct viscosity for airbrushing. The right reducer depends on your paint type:
- Acrylic paints: Distilled water, or a dedicated acrylic airbrush thinner/reducer. Avoid tap water (minerals can affect paint).
- Lacquer paints: Lacquer thinner. Not interchangeable with acrylic thinner.
- Enamel paints: Mineral spirits, white spirit, or enamel-specific thinner.
- Solvent-based urethanes: Urethane reducer.
Why not just use water for acrylics? Water works but can over-dilute the binder, reducing adhesion and durability. A dedicated reducer maintains binder concentration while reducing viscosity, often including additives for flow and drying properties.
Target viscosity: Paint thinned for airbrushing should flow like skim milk — not watery, not thick. It should form a smooth stream off a stir stick, not drip in chunks.
Related: Viscosity · Flow Improver · Binder · Tip Dry Learn more: Airbrush Paint Thinning Guide