Painting in oil is not easy, you need to invest some time and a lot of patience to practice, though the good news is that painting in oil just comes naturally once you get used to it. Here are a few things you should know when you start painting in oil. First, you shouldn't worry about technique when you start painting. Yes, there are some techniques, but they are not difficult, once you start painting they will just come naturally, and you will discover them by yourself. All you need to know for the beginning is that there are two important ways of painting:
DIRECT PAINTING: Some painters prefer working in this technique also called alla prima or wet on wet. I like this technique because I can paint faster and spontaneously, preferably in one session or fewer sessions. Painters who liked this technique were Velasquez, Monet, Van Gogh, Singer Sargent, Chaim Soutine, de Kooning.
INDIRECT PAINTING: Other painters work in layers, to obtain a more detailed painting. These layers can be thin, either the colours are smudged sparingly over darker layers of colours, and then we say that the technique is SCUMBLING, or the layers are transparent and cover entirely the layer underneath or certain areas, like a film. This technique is called GLAZING, and the layers are called glazes. Indirect methods of panting were prefered by Van Eyck, El Greco, Rembrandt, Modigliani, Rouault, Bracque, Paul Klee.
More techniques can be combined in one painting, you don't need to work only in fine glazes, or only scumble colour everywhere.
For scumbling you don't need mediums, you work with dry hard brushes, while for glazing you need a glazing medium, which makes the paint more fluid and transparent. The most popular glazing medium is Liquin Original from Winsor and Newton. The brushes used are fine and soft, like watercolour brushes, more expensive sable brushes can be used by some painters.
Here is an example of fine indirect painting of Lucian Freud:
Later on the artist ditched the fine sable brushes and gave up sitting while painting, for working standing and he started using harsh hog brushes. His new technique was IMPASTO, thick paint was applied for a sculptural effect:
ADVANTAGES OF PAINTING IN OILOil looks better
An oil painting certainly looks more beautiful and intense, and has more depth than an acrylic painting.
Time for blending
You have plenty of time for blending with oils, this is good if you want realistic curtains, shadows and portraits.
Consistency and coverage
Oil paints have a creamy consistency so the blending is easier, plus you will be able to cover a larger surface at the time with one brush stroke than with acrylics.
The palette doesn't dry
You don't need a stay wet palette for oils, you can do your palette in the morning and work with it the whole day. You don't have to worry about damaging your brushes either, because the paint on the brushes won't dry for hours.
Yes, nothing compares to painting in oil, and though there are some disadvantages too.
DISATVANTAGES OF PAINTING IN OIL
Oils dry very slowly, over two days usually, unless you use some fast drying mediums (I used Liquin Original glaze from Winsor and Newton). But the mediums are toxic and have strong odours, plus they can only speed up the drying time to about 24 hours, which is still not enough for many painters. The art works are wet for days and the storage and transport are a problem. If you paint for dead lines like exhibitions, commissions or exams, you need to be extremely organized and finish one week in advance to allow drying.
Another disatvantage is the constant mess around the oil artist. A huge amount of cloths is needed for painting in oil, brushes and paint tubes get dirty. You can overcome this distavantage if you are organised. Cleaning the brushes is time consuming. Turpentine or other solvents damage brushes and are not recommended. Though I find that professional oils nowadays became easier to clean, I use only water and soap.
Oil must be used with care, because of the toxic fumes of the solvents used and the toxicity of the pigments, but if you want to paint like the Old Masters the only choice is oil. So you may use it successfully if you follow the rules.
First open the windows often when you work with oils.
Do not eat or drink in the same room you paint.
Do not let the paints or solvents come into contact with your skin. Wearing some surgical gloves is recommended, because even if many natural pigments have been replaced, some of the most beautiful ones, like cadmium of cobalt, for example, can be quite nasty, and everything that gets onto your skin will go inside too.
Be aware that all mediums, solvents and turpentine have toxic fumes. The good news is that many painters nowadays succeeded in avoiding them. You don't need turpentine or other solvents to make your paints more fluid. I know many painters who use only raw linseed oil or other oils like poppy seeds oil, safflower oil or nuts oil (nuts oil must be stored properly as it gets rancid otherwise). Be aware that the more oil you add, the longer the drying time. The linseed oil has the bad quality of yellowing with time, so poppy seed oil and safflower oil is recommended for lighter colours. I use only the last two because they are light and fluid and slow the drying time, which helps me paint alla prima, wet on wet.The cleaning up can be done with old cloths and cheap vegetable oil, warm water, but not hot (take care of your brushes) and soap. I find that professional paints became much easier to clean in time, I use only water and home made laundry soap, while student quality paints seem still greasy and harder to clean. My home made laundry soap is made in the country in Romania, I don't think is made in other countries I am afraid. I also use an organic nontoxic cleaning medium for brushes.
The paintings in oil can be protected with varnish, but you have to wait ideally for a few months to varnish a painting, because it has to be completely dry. Be aware that varnishing paintings can yellow paintings in time. Look for quality non yellowing varnishes. Apply varnish outdoors or in a well ventilated space.
The fat over lean rule must be followed when painting with oils.
Fat over lean (flexible over less flexible)
When painting in layers, each successive layer must be more flexible than the one underneath.
Thick over thin
Thick layers of oil colour are best applied over thin under layers. Thin layers over thicker layers of impasto paintings are likely to crack.
Slow drying over fast
Slow drying colours should not form continuous under layers as any faster drying layers on top may crack.
It is good to know that oil layers dry at different times if you tend to make some layers thicker and others thinner, or if you add solvents or oils for thinning. You will figure out in time.
For use in the rooms with no proper ventilation, smaller class rooms, or for sensitive people, there are water mixable oils on the market. They are easier to use and you can keep everything clean because the brushes can be cleaned in water during work. Cleaning up brushes after work is a breeze as it can be done with just water and soap. But the watermixable do come with a compromise. In comparison to the artist quality traditional oils, they don't have the same high pigment concentration and the colours chart is limited.
For the ones who want their paintings to dry quickly, there are fast drying oils. They need to be used in a well ventilated space, and they require more attention to the fat over lean rule.