Deciding whether to oil out a painting before you varnish it can be a bit of a dilemma because there’s so much conflicting information online. Add to that the fact that different types of paintings have varying demands in this regard, and that choice gets even harder. But is there a definitive answer to this question, or is this one of the many subjective aspects of art?
You should oil out a painting before varnishing. Oiling out before 
varnishing adds a protective layer to your painting, preserving its colors and fine detail for longer. Oiling out a painting can also be a great way to restore its colors and detail before varnishing.
This article will focus on the importance of oiling out and varnishing. Towards the end is a list of varnishes, isolation coats, and brushes that can assist you on your painting journey and ensure better results for your hard work.
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Should You Oil Out a Painting Before Varnishing?
Oiling out your paintings (also known as applying an isolation coat) happens after thoroughly drying your artwork. It’s the step between drying and applying varnish.
Applying an isolation coat adds a protective layer to the paint. It ensures that when the painting is being cleaned in the future (after removing the outermost layer of varnish), there is still that oiled-out layer protecting the original paint and colors from being tampered with. Even if you don’t end up using varnish, you can rest assured your painting is greatly more protected.
Oiling out a painting can also be a great way to restore the finish and even out the paint’s colors.
Sometimes, you might notice that some colors look duller while others look shinier than they initially started. This is known as sinking in, a phenomenon common in oil paintings. Sinking in can cause paintings to lose their vigor, so you want to avoid it by oiling out your paintings before varnishing.
Oiling out can also be beneficial for an artist looking to apply a fresh coat to a painting. It re-saturates existing colors and prepares the surface for the new coat of paint to make application easier. Without an isolation layer, the surface will be too dry to soak in the new coat, and you’ll end up with a painting that any keen eye can tell was done several times.
Can I Varnish a Painting Without Oiling it Out?
Whether you can skip applying an isolation coat depends on the type of painting you’re working on. To clarify this, let’s look at which of the three most common types of paintings can be varnished without an isloation layer and the risks involved.
Acrylic paintings need an isolation coat; varnishing without one opens up these paintings to all kinds of damage when you remove the varnish at a latter date. But if you don’t intend to remove the varnish down the line, you can skip oiling out.
Watercolor paintings also need an isolation coat before varnishing. Otherwise, the varnish can’t be removed later on without altering the painting’s color and texture. But if you intend to leave the varnish on the painting permanently, you can skip oiling out.
Things are abit different for oil paintings. Oiling out isn’t a necessity for these paintings because oil paint is less likely to be damaged by the solvents used to remove the varnish. As long as you dry the painting completely before varnishing, removing the varnish in the future won’t affect the color and detail.
How to Oil Out a Painting Before Varnishing
There is more than one way to oil out your paintings, depending on what you’re comfortable with and what works for you. You can use a brush, cheesecloth, or a lint-free piece of cloth. Whatever you use, be sure to apply the coat as thinly and evenly as possible.
You also want to make sure you use the right isolation coat for your painting type. For acrylics, the isolation coat is a gloss gel medium mixed with water. On the other hand, the isolation coat for oil paintings is usually a thin coat of oil combined with a solvent.
Having covered what to use, let’s get to the actual steps:
- Make sure your painting is fully dry, as you might damage it if you start oiling out while it’s still wet.
- Use linseed oil and a lint-free cloth.
- Soak the cloth with the oil and gently dab around the painting till you hit all the spots.
- Remove excess oil with another cloth.
- Repeat the process if necessary (but not more than once or twice.)
- Wait at least one or a few days for the layer to dry before applying the varnish.
The Importance of Varnishing Paintings
Oil paintings used to take around six months to dry thoroughly before you could apply varnish. Now, however, you can varnish your paintings after about a week. Other factors contribute to its drying, including climate and how thick you applied the paint.
Varnishing your paintings makes their colors pop and look richer. It also adds an overall shine. On the other hand, skipping varnishing leaves your paintings open to collecting dust and other random things that can stick onto the paint.
Another reason to varnish is to make it easier to clean. If there’s no protective layer between the paint and the cloth, you will undoubtedly be ruining the paint by scraping it off unintentionally and messing up its shine.
Final Words
Art is one of the most subjective expressions of one’s mind. However, whether oiling out before varnishing is necessary is far from subjective; most types of paintings need oiling out to preserve their vibrance, detail, and longevity.
Oil paintings are the only exception. These may be fine without an isolation coat because oil paint is rarely damaged by the solvents used to remove varnish. Still, oiling out is recommended for these paintings in other instances, such as when restoring old paintings or applying a fresh coat of paint.