Like all artistically paintable colours, oil paint consists of a binding agent and colour pigments. The special feature of oil paint is the high proportion of oil in the binder. Since oil cannot be mixed with water, turpentine is used as a thinner. For health reasons, it is not advisable to use a cheaper turpentine substitute (DIY store). Oil as a binder is very well suited for use with pigments, because it hardly or advantageously changes their structure. Oil paints are very durable and lightfast. As a rule, they are opaque. By applying a thin layer of paint or thinner, oil-based paints can also be applied semi-transparently (translucent). For centuries artists have been working with oil paint and have created paintings that hang in museums all over the world.
Bestandteile der Ölfarbe
As a rule, the oil is obtained from natural products of local, but also exotic plants:
- Linseed oil (flax)
- Nut oil (walnut oil)
- rapeseed oil
- sunflower oil
- poppy seed oil
- hemp oil
- safflower oil
- castor oil
- perilla oil
- Tung oil (Chinese wood oil)
- Oiticica oil.
Meanwhile synthetic oils are also produced by the industry.
The range of colour pigments that can be used is very wide - and in principle all pigments can be used that are also suitable for other binding agents (e.g. gum arabic for watercolors).
Eigenschaften der Ölfarbe
The oil is "thickened" for oil paint. If you buy oil paints in a tube or in cans, they usually have a paste-like viscosity (similar to toothpaste from a tube). With it, one can create the typical pasty traces of paint on the canvas.
In some brands, other substances are added to the binder, e.g. so-called siccatives, which accelerate the drying process.
The light fastness of oil paints is usually very high. This is, of course, also due to the fact that manufacturers have been carrying out corresponding tests with the pigments for decades. Nevertheless, differences can be found, especially with old, traditional shades. A low light fastness leads to fading of the colours over the years. From a chemical point of view, the colours decompose due to light irradiation, or in particular UV radiation. On the tubes of most manufacturers the light fastness can be seen from a series of five stars: one star = low light fastness, five stars = high light fastness.
Oil paints usually have a high opacity, which means that after the application of the paint the underlying layer is completely superimposed. Some colors, however, are only semi-transparent due to their pigment structure. The degree of transparency can be increased by dilution. On the tubes, the opacity of the color is represented by five squares: one square = low opacity, five squares = high opacity.
Oil paints in tubes or cans
Artist oil paints can be bought in tubes or cans. The content is usually between 25 ml (something as thick as an index finger) and 400 ml (very large tubes). In ancient times - from the development of oil painting from Jan van Eyck in the 14th century to the middle of the 19th century, for example - oil paints were always made shortly before the painting process. For this complex process the artist needed a relatively large workshop and mostly also employees (apprentices).
Invention of the oil paint tube
At the beginning of the 19th century a breakthrough came: the American painter John G. Rand (1801 - 1873) invented the oil paint tube. The lockable, airtight tube made it possible to store oil paints and transport them easily. These completely new possibilities brought plein air painting to life in nature and paved the way for Impressionism and modern painting. For more information see History of Oil Painting
What happens when the oil paint dries?
In the chemical sense, oil paint does not dry at all, at least not by evaporation. In contrast to water-paintable paints (tempera, gouache, watercolor), the paint does not become solid because the "liquid" components evaporate in the air. Although the turpentine components evaporate from the paint, it is by no means "firm to the touch" or "thoroughly dried".
Chemically speaking, the oil paint oxidizes and polymerizes. These processes can take decades. In a pasty oil painting, the "drying process" is only completed after centuries. But, of course, after some time the surfaces are closed enough that the picture can be touched. For the sake of simplicity, the term "drying" is used in the following for this oxidation process.
When drying the oil paint, it should be noted that it initially expands, i.e. increases in volume. In this time the picture can "shrink": especially if pure oil like linseed oil is added to the oil paint, a wrinkled layer usually forms. After some time, this process reverses and the paint contracts again, thus losing volume. If the paint layer is applied thinly and the drying process is accelerated by a siccative, it can form cracks, especially if the underlying layer has not yet dried but is in the expansion phase.
These chemical changes cause an increase in viscosity (toughness) up to complete curing. Since oxygen is required for the reaction, the outer layers dry first. For this reason, oil paint cannot simply be stored in the air. If you already have some experience with oil painting, you will know that the paints on the palette get a thin firm skin overnight. An oil painting in a vacuum would not dry at all. However, there are considerable differences in the drying speed of individual colours. For example, Prussian blue dries on the surface within a few hours, while titanium white, for example, remains workable for up to 10 days as on the first day.
If the picture carrier (wood or canvas) distorts in the course of the years weather-conditioned, it can come to cracks on the surfaces of oil paintings. These net-like structures are called craquelure.
How long does oil paint take to dry?
How long it takes to reach this gripping condition depends on ...
- the oil used
- of the colour pigments used
- from the primer (!)
About the thumb you can say for a grippeste surface:
- a liquid painted oil painting needs about 1-2 days to dry
- a painted oil painting needs about 4-6 days to dry
- a pastily painted oil painting needs about 8-12 days to dry ()
However, it is by no means recommended to use strongly sucking substrates to accelerate the drying process. On the contrary, if the oil paint loses too many liquid components too quickly during the oxidation process (described above), it becomes slightly brittle and loses its luminosity.
Oil paint on canvas (detail)
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 helpful, for example, with a coloured, glazed background. The undercoat thus acts like the last layer of the primer.
In pastel paintings, the drying process is independent of the primer - since the paint "dries" on the surface as a result of the effect of air.
Oil Paint can be easily diluted and painted with turpentine oil or balsam-terpentine oil. This makes the shade more liquid, so that it can also be applied semi-transparently (glazing). Liquid oil-based paints can also be used to create similar lavender effects to watercolors (if the colours flow into each other). However, a relatively little absorbing ground is necessary for this.
The drying process is faster with diluted oil-based paint because the turpentine content of the paint evaporates relatively quickly in the air - it is therefore an actual drying process (for more information see above).
Cleaning / Workwear
Oil paint is very difficult to clean in textiles. You will have to get used to oil paint stains on carpets or clothing. You can try to dilute the paint with turpentine oil. However, it will be possible to remove it completely from the textile. It is therefore advisable to put on appropriate work clothes (painting smock, painting shirt and painting trousers). Oil paint can almost no longer be completely removed from leather. So also think about your shoes.
The cleaning of the brushes is usually done in two steps:
- Coarse pre-cleaning with turpentine oil or a special brush cleaner.
- Washing out with soap
The second step in particular makes a significant contribution to ensuring the quality of the brushes in the long term.
Hand washing / oil paint on the skin
Oil paint in itself is not harmful to the skin. Also here applies: first wipe off the coarsest with brush cleaner or balsam-terpentine oil, then rinse thoroughly with soap. The turpentine oil or the brush cleaner can dry out the skin and make it brittle. It is therefore advisable to apply cream to your hands afterwards, or to work with gloves from the outset (which, however, dissociates the painting process unpleasantly).
Attention! In very few cases there may be an intolerance which can lead to allergic reactions.
Siccatives are additives that can be added to the oil paint. Siccatives are available in small bottles from specialist art dealers. However, you should be careful when adding them. For more information.
Oil paints Basic equipment
It is usually sufficient to have 5-6 tubes of oil paint first. I would recommend the following colours as an introductory set:
- White (you usually need a lot of it)
- (Lights) Ochre (basic colour often used for mixing)
- Cadmium yellow (you need a lot of it if you want to paint green clay)
- Chromium dioxide green or permanent green (you usually don't need much of this because you mix it with yellow)
- Ivory black (rarely necessary, can be little) - instead often a dark shade offers itself: Prussian blue or Vandyck brown
In principle, you can mix almost all the other tones together from these colours.
If you like, you can also start with a starter set, which often contains 20 - 30 tubes with finely differentiated colours. However, you will probably soon notice that you need at most half of them.
Manufacturer of artist oil paints
The best-known manufacturers of oil paints that can be bought are:
- Schmincke - brands: Norma, Mussini, Academy
- Lukas - brands: Lukas 1862, Studio
- Winsor & Newton - brands: artist oil paint, Winton, Artisan, Griffin
- Talens - brands: Rembrandt, van Gogh, Amsterdam
- Daler-Rowney - brands: Artist's oil
- Kreul - brands: Goya
- Boesner - brands: Oil Studio
- Bon Ross oil paint (expensive, medium quality)
- Portable easel
- Introduction to oil painting (for beginners) - Overview
- History of oil painting
- The special feature of oil paint
- How toxic are oil paints? Is oil painting dangerous?