Understanding Varnish and its Importance
Varnish is a protective coating applied to a finished painting, often done after the painting has completely dried. It is an essential process to ensure that the painting does not deteriorate, lose its sheen, and retains its original color.
Art restoration experts consider varnishing as a crucial final stage in oil painting, as this layer provides a barrier that shields the paint film and protects it from dirt, dust, smoke, and even pollutants, preventing discoloration and mildew growth.
However, varnishing is a delicate process, and a wrong application can negatively impact the painting. Therefore, it is important to understand the varnishing process, the types of varnishes that you can use, and how to apply them.
Types of Varnishes for Oil Paintings
There are different types of varnishes that you can use for your oil paintings. However, the two most popular varnishes are:
- Damar Varnish: This is a traditional natural resin sourced from the damar tree and is soluble in turpentine. Damar varnish dries to a glossy finish but tends to yellow over time.
- Retouching Varnish: This varnish is synthetic and is a temporary varnish used to protect your painting until the final varnish can be applied. Retouching varnish does not penetrate the paint layer but sits on the surface.
How to Varnish Your Oil Paintings
The following steps will help you properly varnish your oil paintings:
- Clean your painting using a soft dry brush or a piece of lint-free cloth to remove any dust or dirt on the surface.
- If you are using damar varnish, dilute it with turpentine in a 1:2 ratio. Only a thin layer of varnish should be applied to the surface; it should not obscure the texture or details of the painting.
- Start applying the varnish from the top of the painting, using horizontal or vertical strokes. Avoid using circular strokes, as it can lead to streaks or bubbling. Work in a well-ventilated area and make sure your workspace is free of dust.
- Let the painting dry completely before applying a second coat, which should be done within 24 hours.
- After the second coat is dry, leave the painting in a horizontal position for at least two days to prevent dust or hairs from settling on the surface.
Additional Tips
Here are some additional tips to keep in mind when varnishing your oil paintings:
- Do not apply varnish to an unprimed canvas; it will seep through and cause damage to the canvas fibers.
- Ensure that your brushes are clean and dry before starting the varnishing process to avoid leaving debris or streaks on the painting.
- If you are not confident in varnishing your painting, consider hiring a professional.
- Store your varnish in a cool, dry place, and make sure the lid is tightly closed. Note that varnish has a limited shelf life and should be replaced when it appears cloudy or thick.
- Varnish your painting after it is completely dry, which can take up to six months depending on the thickness of the paint layers.
