Oil paint: components and properties

Oil paint consists of a binder and colour pigments. The special thing about oil paint is the high oil content in the binder. Since oil is immiscible with water, turpentine is used as a thinner. The cheaper turpentine substitute is not recommended for health reasons. Oil is very suitable as a binder for use with colour pigments, because it does not or hardly change their structure. Oil paints are therefore very durable and lightfast. In general they are opaque. By applying a thin layer of paint or thinner, oil paint can also be made semi-transparent. For centuriesartists work with oil paint and have created paintings that hang in museums all over the world.

Components of oil paint

The oil is usually obtained from natural products of native, but also exotic plants:

1. Linseed oil (flax)
2. Nut oil (walnut oil)
3. Rapeseed oil
4. Sunflower oil
5. Poppy Seed Oil
6. Hemp oil
7. Safflower oil
8. Castor oil
9. Perilla oil
10. Tung oil (Chinese wood oil)

The colour pigments that can be used are very wide - and in principle all pigments that are also suitable for other binders can be used.

Oil paint properties

The oil is "thickened" for oil painting. When you buy oil paint in a tube or can, it usually has a paste-like viscosity (a bit like the toothpaste in the tube). This allows you to leave the typical pasty painting marks on the canvasto make.

Some brands add other substances to the binder, e.g. so-called siccatives, which accelerate the drying process.

The lightfastness of oil paints is usually very high. This is of course also due to the fact that the manufacturers have been conducting adequate tests with the pigments for decades. However, differences can be observed, especially in old, traditional colour tones. Low lightfastness leads to the colours fading over the years. From a chemical point of view, colours are broken down by exposure to light, especially UV radiation. On the tubes of most manufacturers theLightfastness is indicated with a series of five stars: one star = low lightfastness, five stars = high lightfastness.

Oil paint usually has a high hiding power, which means that after applying the paint the underlying layer is completely covered. However, some paints are only semi-opaque or semi-transparent due to their pigment structure. The degree of transparency can be increased by thinning. The opacity of the paint is indicated on the tubes with five squares: one square = low opacity, five squares = high opacity.

Oil paint in tubes or cans

Oil paint for oil painting is available in tubes or cans. The capacity is usually between 25 ml (slightly the thickness of an index finger) and 400 ml (very large tubes).

Invention of the oil paint can

The lockable, air-permeable tube made it possible to store oil paints and transport them easily. These completely new possibilities revived plein air painting in nature and paved the way to impressionism and modern painting. For more see History of oil painting.

What happens if theoil paint dries?

Chemically, oil paint does not dry at all, at least not through evaporation. Unlike water-based paint (tempera, gouache, watercolor paint), the paint does not solidify because the "liquid" components evaporate into the air. Although the turpentine components evaporate from the paint, it is by no means "solid to the touch" or "completely dry."

Chemically, oil paint oxidizes and polymerizes. This process can take years. In the case of a pasty oil painting, the "drying process" is only completed after decades. But of course over time the surfaces are sealed in such a way thatpainting can be touched. In the following - for the sake of simplicity - the term "drying" is used for this oxidation process.

How long does it take for oil paint to dry?

How long it takes to reach this grip-stable state depends...

1. on the used oil
2. the colour pigments used
3. on the primer (!)

About the thumb one can say, for a grippy surface:

1. a liquid painted oil painting (lots of painting medium, thin layers of paint) takes about 1-2 days to dry.
2. a normal oil painting takes about 4-6 days to dry
3. a pasty oil painting (visible elevations higher than 1 millimeter) takes approximately 8-12 days to dry.

However, it is not recommended to use highly absorbent surfaces to accelerate the drying process. On the contrary, if the oil paint loses too much moisture too quickly during the oxidation process (described above), it easily becomes brittle and loses its luster.

However, it is by no means recommended to use highly absorbent substrates to accelerate the drying process. On the contrary, if the oil paint loses too much moisture too quickly during the oxidation process (as described above), it easily becomes brittle and loses its clarity.

The primer

With an absorbent primer the drying time can be reduced by almost half, but only if the oil paint is applied thinly and diluted with turpentine oil. This can be useful, for example with a coloured, glazed underpainting. The underpainting therefore works as the last layer of theprimer.

In the case of impasto paintings, the drying process is independent of the base coat - as the paint "dries" on the surface due to the effect of the air.

Dilution of oil paint

Oil paint can be easily diluted and painted with turpentine oil or balsam turpentine oil. This makes the paint more fluid, so that it can also be applied semi-transparent (glazing). Liquid oil paint can also be used to create similar lavender effects as with watercolor paint (when the colours blend together). However, this requires a relatively non-absorbent background.

The drying process is faster with diluted oil paint, because the turpentine components of the paint evaporate relatively quickly into the air - so it's a matter of actually drying (for more on this, see above).

Cleaning oil paint

Oil paint is very difficult to clean in textiles. Oil paint stains on the carpet or clothing will take some getting used to. Although you can try to thin the paint using turpentine oil. But one will be able to remove it completely from the textile. It is therefore advisable to purchase suitable work clothing. It is also almost impossible to completely remove oil paint from leather. So also think about the shoes.

Cleaning the brushes is usually done in two steps:

1. Rough pre-cleaning with turpentine oil or a special brush cleaner.
2. Wash out with soap

The second step in particular contributes to the long-term quality of the brushes.

Hand washing / oil painting on skin

Oil paint in itself is not harmful to the skin. Here too, first wipe off the worst with brush cleaner or balsamic turpentine oil, then wash thoroughly with soap. The turpentine oil or brush cleanser can dry out the skin and make it brittle. It is therefore advisable to rub your hands with cream afterwards, or to work with gloves from the start (although this makes the painting process unattractively distant).

Caution. In very rare cases, there may be an intolerance, which can lead to allergic reactions.

The arrangement of the oil paints on the palette

How to beapplied the colours to the palette? Basically, there is no "right" answer. The most important thing is that the colours you want to mix are placed next to each other as much as possible. Then you can use the brush in one colour or the other and draw in the mixing colour between them. This way you can create even the finest colour shades.

Which colours are used naturally depends on the chosen motif. Those who paint portraits will use more ocher, yellow and red tones. Those who paint northern landscapes will have more ocher and blue tones on their palette.

Paint by Numbers: oil paint or acrylic paint?

At the Paint by Numbers only acrylic paint is used. The reason we use watercolor is that it is the easiest form of painting at an amateur level. Want more information about acrylic paint? Then read our blog article: '' Acrylic painting for beginners: accessories, techniques and tips ''