Oil painting has a long history in the art world. This medium offers a wide choice of colours ranging from rich and velvety dark tones to vivid and brilliant hues. It allows us to create a whole range of different effects, from translucent layers (glazes) to thick, creamy impasto. Learn more about oil paint colours.
Oil paint is made of ground powder pigments in oil to produce a smooth and homogeneous paste.
1- Paint quality
Oil paint, like other mediums, is produced in both fine (less expensive) and extra-fine ranges.
The more finely ground the pigments, the easier the paste is to work with and the better its coverage. Pigments' particle size influences paint quality and is one of the elements that differentiates fine and extra-fine paints. Pigment concentration is higher in extra-fine pigments and they contain less binder, which is why they are more expensive.
2- The drying process
Oil paint dries not by evaporation, but by oxidation. The oil hardens by absorbing oxygen from the air. The thicker the paint layer, the longer this process takes. The complete drying process can take anywhere from a few months to a year.
Light also plays a role in the drying process. Diffused natural light offers the best drying conditions. For this reason, it is not advisable to dry your canvas in a closet or in a dark place, as the darkness will cause the paint to soften and yellow. Conversely, avoid placing your canvas in bright light, such as in front of a window, because too much direct light can cause a brittle paint film.
Oil colours do not change as they dry. The pigments that make up the colours have distinct properties. Some absorb more oil than others, so colours vary in drying time. Depending on the colour, the paint will be dry to the touch between 2 and 14 days. (It may take several months for the paint to dry completely.)
3- Water-soluble oil paints
Water-soluble oil paints are true oil colours because they do not contain water. The oils that bind the pigments are chemically modified to be water-soluble. These paints have the same drying and consistency properties as conventional oil paints, but have the added advantage of being nearly odourless and using no solvents. The water will serve to dilute the paint instead of the solvent.
Manufacturers have also developed mediums and additives that are complementary to water-soluble oil paints. Traditional mediums can be used, but they may alter the specific characteristics of water-soluble oil paints if used in large quantities. It is therefore recommended to only use mediums and additives specifically designed for water-soluble oil paints.
4- Safe use
It is important to follow basic health and safety guidelines when using oil paints to avoid risks associated with the toxicity of certain pigments and solvents.
Colours based on lead, cobalt, cadmium, mercury, manganese, chromium and antimony pigments sometimes contain heavy metals and must be handled with care. Pigments from heavy metals are increasingly being replaced by alternative pigments that are considered safer.
Toxic pigments are increasingly being replaced by non-toxic pigments. The term "hue" or "Imitation" generally indicates that the colours are made with substitute pigments. We also see the term “azo” used to identify alternative colours.
In Canada, the concentration of pigments from heavy metals is too low to require a warning label according to Health Canada regulations. What remains dangerous, however, are solvents, such as turpentine, which smells very strong and is toxic. Manufacturers offer alternative solvents to turpentine that are less offensive in odour. However, even odourless solvents should be handled with care, as they are still toxic.
Best practices for oil painting:
- Ensure your studio is properly ventilated
- Always clean your hands after working with oil paint (e.g. before eating)
- Avoid touching the paint with your fingers
- Avoid putting the brush in your mouth (even if it has been cleaned)
- If any product comes into contact with your skin, rinse your skin immediately and thoroughly
- Avoid smoking, as products that complement oil paints (such as solvents) are flammable
- Dispose of paint tubes and containers according to the environmental standards of your region, or return your tubes to a participating DeSerres store as part of our Re(Art) program.
These colours, unlike imitations of cadmium, have the same characteristics and qualities as colours with cadmium, namely a remarkable opacity and light-resistance which guarantees colour permanence. Cadmium-free colours are now available in Winsor & Newton's professional line of Artists' oils.
Oil paints cannot be used the same way as acrylics. The binders that are used in oil paints give them exceptionally fine and durable finishes, but they must be used in limited ways. Oil paint is best suited to cotton or linen canvas, or other textiles. The canvas may be primed with gesso before use to ensure better paint adherence. Oil paint is not suitable for painting objects. The paint will only adhere to a surface if it offers the right balance between flexibility and rigidity, as well as between absorption and water-resistance. Canvases are now almost always primed with gesso for better adhesion but also to ensure that the colour does not seep through the cotton and to avoid any surprises (e.g. cracks, mold, etc.)
- Avoid painting leather clothing even if the fabric can be painted.
- Avoid using oil paints outdoors, as the paint film cannot withstand weather conditions.
Golden rule for oil painting: “Fat over lean”
The “fat over lean” rule involves ensuring that your new layer of paint has a higher oil content than the previous layer. The oil makes the paint fat while the solvent makes it lean. Applying this golden rule to your painting will prevent the formation of cracks or "orange skin" effects when the paint dries.