It is a question that you have surely asked yourself after wanting to continue painting a picture and find that when you pass the brush, the colors mix with those of the lower layer, or are dragged, revealing the white canvas in that area. how much effort it took you to achieve.
This situation will undoubtedly have put off a lot of beginners, I hope not you, and that you can realize that the drying time of oil paint is a wonderful property of this material since it allows you to work more slowly and make corrections, smudges, and other fantastic effects that with other paints are difficult to achieve. I recommend you read the article: What you should know about oils for oil painting.
There are several aspects that influence how long a coat or finished painting will take to dry, but to begin with, I will explain that there are two types of drying:
1. Drying time to the touch
It’s when you run your fingers over the paint and it doesn’t get painted or doesn’t feel sticky. However, applying a lot of force or wiping solvents with a cloth can cause paint to peel off. In thick layers, the surface will be dry but underneath it may still be too cool. It can vary from one day to a week.
2. The actual curing or drying time
It is the time it takes for the paint to fully harden through the oxidation process that air produces when interacting with it. Depending on the thickness of the layers, it can vary from six months for thin layers to a year or more for thicker ones.
Factors affecting both drying times
Manufacturer and brand of oil painting:
Some grades have more binder oils than others, so they will take longer to dry.
Type of pigment:
Some pigments by their nature have a longer drying time than others or require more or less oil to give them an adequate consistency during their manufacture. Some dry to the touch in a day, others may take up to 10 days.
Type and quantity of means employed:
Different types of media can be applied to extend the drying time or to shorten it. Among the most common, we have the turpentine that is used alone in the first layer and has a very fast drying by evaporation, as well as the simple half linseed oil/turpentine, which will dry slower as it has more oil. (Remember to vary the proportions in each layer respecting the Fat over Lean rule ). In the trade, you can find different types of linseed oil with variable drying times. There is also poppy oil for quick-drying, as well as modern alkyd media that speed it up even more, such as liquid or Galkyd.
It should be clarified that the behavior over time of oils and alkyd media has not been proven for enough years (they began to be used since 1950) to ensure good conservation of works painted with these materials, but the opposite cannot be proved either.
They also sell drying accelerators, especially cobalt ones, however, I, as well as many artists, recommend not using them, as they can deteriorate the colors and produce cracks. I have always thought that the slow drying time of oil paints is one of their wonderful qualities, and it is best to let the paint dry naturally. I recommend working on two or three canvases, so you can paint on one while the others dry.
Of course, the more paint the layer has, the longer it will take for oxygen to penetrate into the deeper parts, delaying its drying. The thinner the layer, the more interaction with the air, and the faster oxidation and other reactions take place that harden the oil.
The climate of the place:
Cold, humidity, and lower wind speeds extend the drying time of oil paint.
The type of support:
Of course, the type of support, especially its preparation, can affect its drying as its surface is more or less absorbent. Thus, when the substrate primer absorbs some of the oil, the paint will dry faster. This property must be balanced since there must be a degree of absorption to promote adhesion but not so much as to dry out the paint (it becomes brittle) or deteriorate the support.
Conclusions on drying time
– Using traditional oils and a common medium such as linseed oil/turpentine, a thin layer of oil could be dry to the touch after two days or a week of painting, depending on the factors already listed, especially depending on the colors used ( I will expand on this in the next article). For its part, a thick, pasted layer could take from 15 days to a month for its surface part to be dry to the touch only.
– If your painting was painted with thin layers, with moderate use of oil, and the climate in which you find yourself favors drying, you could consider it fully cured after 6 months of painting. If, on the other hand, your painting is made with large pastes and you live in a cold and humid climate, you should wait more than a year, and even longer, to assume that your work is completely dry inside.
– To give the painting other layers where you do not want the colors to mix with those of the lower layer, it can be enough to wait for it to be dry to the touch. However, to give the final protective varnish to your work (this is optional) you must make sure that a prudent curing time has passed, otherwise, the varnish will prevent oxygen from reaching the paint and harden it completely.