Oil paint becomes smooth primarily through the addition of painting mediums or by thinning it. These substances alter the paint's consistency, making it flow more easily and reducing brush strokes or texture.
The Role of Mediums in Achieving Smoothness
Oil paints, straight from the tube, can be quite viscous and retain brush marks. Painting mediums are added to change the paint's working properties. When aiming for a smooth finish, mediums are used to reduce viscosity and improve the paint's flow and leveling capabilities. By diluting the paint, these mediums allow it to spread more evenly across the surface.
Key Medium Types for Smooth Results
Various mediums can be used to make oil paint smoother, each offering slightly different characteristics and drying times.
- Thickened Oils: Certain types of refined oils, like thickened linseed oil or stand oil, are excellent for achieving smooth results, particularly for creating even, translucent layers known as glazes. As mentioned in the reference, Stand oil is a thickened linseed that is good for making even, smooth glazes. Its syrupy consistency helps the paint level out beautifully.
- Alkyd Mediums: These synthetic resin mediums are designed to thin oil paint, increase its drying speed, and improve flow. A popular product by Winsor & Newton called 'Liquin' is an alkyd-based solution designed to dilute oil paint and increase its drying speed and viscosity. While it adds viscosity compared to a solvent, its diluting effect often leads to a smoother, more self-leveling application than un-thinned paint.
- Solvents: Traditional solvents like turpentine or odorless mineral spirits can also thin oil paint, making it flow more easily and achieving a smoother, matte finish. However, excessive use can weaken the paint film.
Here's a brief overview of how some common additives affect smoothness:
| Additive Type | Primary Effect on Consistency | Resulting Smoothness | Notes |
|---|---|---|---|
| Stand Oil | Reduces tack, increases flow | Excellent for smooth glazes | Thickened linseed oil (per reference) |
| Alkyd Mediums | Dilutes, increases flow/leveling | Good for smooth layers | E.g., Liquin (per reference); speeds drying |
| Turpentine/Solvent | Thins, reduces viscosity | Smoother, often matte | Use sparingly to maintain paint film integrity |
| Un-thinned Paint | High viscosity | Textured, brush marks | Directly from the tube |
By carefully selecting and adding a suitable medium, artists can transform the working properties of oil paint to achieve a sleek, smooth finish.
