The age-old advice to wait at least six months before varnishing oil paintings is a good practice, but one that is resisted by many artists. And it is understandable why because when a painting is completed it often needs to be delivered immediately for exhibit or into the customer's hands.
If a painting has lost its vitality and become dull, all may not be lost. This usually occurs due to what is known as “sinkingâ€, when the top layer of oil has been lost to the layer underneath. There are three common causes: an over-absorbent surface, using too much solvent, or not using enough medium.
Cracking can be avoided by making every subsequent layer a little fatter. 'Fat over lean' can therefore also be interpreted as 'elastic over less elastic'. This makes it immediately clear why a paint layer needs to dry sufficiently before applying the next layer.
It may seem to be a good idea to use a hair dryer to dry oil paints. But it will not work very well. As oil paints dry because of oxidation reactions the evaporation of water caused by the heat of the hairdryer will not speed up the drying time and may even cause your painting to crack.
Here are the five steps you should follow when beginning oil painting.
- Step 1: Gather Your Materials.
- Step 2: Set up a Safe Work Space.
- Step 3: Prime Your Canvas.
- Step 4: Outline Your Painting.
- Step 5: Layer Your Paints.
- Step 1: Wipe off Excess Paint with a Rag and Solvent.
- Step 2: Wash With Warm Water and Detergent.
Spray the entire canvas, front and back, using Mod Podge clear acrylic sealer (or your acrylic sealer of choice). Make sure to follow the instructions on the can. Spray a second layer after the canvas has fully dried for added protection. And that's it!
The first varnish that should be applied to an oil painting is the retouch varnish. Retouch is a traditional varnish that has a lot of solvent and a little bit of damar resin. It's applied as soon as the oil color is dry to the touch. It's meant to protect the painting and bring all the colors up to an even sheen.
Can You Paint Over Varnish? The quick answer to that question is – yes, you can paint over varnish. That is, given that both the varnish and wood are in good condition. If you are planning a painting project that involves coating varnish it's important to take a look at the condition of the varnish and wood first.
Varnish is a hard, protective, removable coat applied over the painting surface. There are two types of varnish that can be used on an acrylic painting: Mineral spirit-based (MSA)—You can use this over anything, but it's extremely important that you have good ventilation. Polymer varnish is not made to be painted over.
Cleaning of painting: The painting should not be regularly cleaned, but only when required. The front of the painting should be cleaned gently with a soft brush to remove the loose dust on the painted surface, alternatively a soft micro fibre cloth can also be used as the painting requires soft treatment and not harsh.
Although acrylics dry quickly on the surface, you should wait at least a week before varnishing to make sure that the acrylics have dried through all the way. Even if an acrylic painting is dry to the touch hours after painting, it is often still a bit wet underneath.
Linseed oil, Galkyd, Walnut Alkyd Medium, and Liquin (or any oil mediums that indicate fast on the label) when mixed with oil paint will speed up the drying time. Using a quick drying medium can dry your paint overnight.
2-3 layers should be fine, a sprayed coat of varnish will dry within 10 minutes and subsequent coats can then be applied, always allow the previous coat to dry first.
It is essential that you varnish your completed acrylic paintings. The varnish will protect the painting from dust, UV rays and yellowing. The varnish will inevitably cause a glare if light is flashed upon it, making it difficult to photograph. I always photograph and/or scan my paintings before varnishing.
How to apply a spray varnish
- Wipe over the surface with a lint-free cloth.
- Place your painting vertically in a dust free room.
- Place your painting on top of a board that is larger than the canvas.
- Shake, Shake, Shake… and then shake some more.
- Apply the spray at an even distance away from the canvas.
Owing to its polymer-forming properties, linseed oil can be used on its own or blended with combinations of other oils, resins or solvents as an impregnator, drying oil finish or varnish in wood finishing, as a pigment binder in oil paints, as a plasticizer and hardener in putty, and in the manufacture of linoleum.
What does a Varnish do for a Painting? The varnish layer plays a dual role: it has and effect on the final appearance of the painting and also serves as a protective coating for the paint surface. Varnishes intensify the appearance of pigments on the painting surface by the refraction of light.
It takes an oil painting somewhere between a few months to a year to dry completely. As a result, oil paintings can become dull and faded with time and there is only a little one could do to restore them.
