As I discussed in my previous weekly insight Oil paint is very flexible. This is so because of its composition. It contains
- Coloured powder pigment,
- Oil (usually linseed which carries the pigment and binds it together)
- A diluent (usually pure turpentine) which controls the consistency.
Here I will discuss guide to four consistencies oil paint with various technical uses.
Wash – To start a painting use paint thinned with additional pure turpentine. Can see the white canvas through it.
Lean Paint – Thin layers with little oil this is a consistency which contains medium which has little oil (lean medium) When its put on the canvas its thin but with colour compared with a ‘wash’ as above. Used in Alla Prima wet on wet.
Fat Paint (impasto) – Very thick straight from the tube, buttery, smooth texture which holds a crisp shape or mixed with a medium with more oil – this is called ‘fat’ paint. Used in final build up as slabs of texture. Applied after thin washes or lean paint mixture is applied.
Encaustic – By adding melted wax (usually bees wax) the oil paint is given greater bulk. The same amount of oil paint may be extended up to twice the amount, to create a thick impasto.
There are basically three methods of painting
1. Alla Prima
The “in one go” method uses wash, lean, Fat impasto and encaustic consistencies.
Alla Prima allows the artist to manipulate the paint over the entire surface of the canvas in one session. While the painting can be changed at any time when completely dry., the idea of the alla prima is to capture the subject/moment in wet on wet paint at the one attempt. The result of this method is a very spontaneous free flowing style. It seems to capture something of the essence rather than a more controlled work of wet on dry paint.
It is important to stop before you want to or get a friend to take the brush out of your hand. Then take it home and let it rest until you are sure you want to change it and then think again before touching it. There is something very special, unique about this moment in time which cannot be captured again, ever.
The famous works of the 9 x 5 cigar box paintings by Arthur Streeton and others of the Heidelberg School demonstrate the brilliance of this method.
2. Method of ‘Fat Over Lean’
This is a ‘go slow’ method of lean, fat and encaustic consistencies where the paint is built up over a period of time. Start the painting with thinner paint that has less oil medium (lean paint) and build up subsequent layers using medium with more oil (fat) This principal is called ‘fat over lean’. It is important to dry each layer thoroughly as the drying occurs through a process known as oxidisation. When oil paint oxidises, skins of pigment form and lock the surface not allowing moisture to escape thus causing cracking or form pools or ripples on the top layer of the oil paint as the surface is disrupted by the unstable layer underneath.
3. Method of Glaze
This is a ‘go slow’ method of a series of thin transparent layers of paint mixed with an additional oil medium that is applied after each layer is dry. It is also important for each layer to dry thoroughly before adding another layer. The thin transparent layers of paint allow the light to go through all the layers like a reflective pool of water or mirror. Any paint with white added to it will block the light layer.
Oil paint takes longer to dry in humid and cooler weather conditions. You may use this to your advantage with some paintings. There are different mediums available to enhance drying times of oil paint. You will develop a greater control in your painting when you become used to the particular qualities and drying times of each oil paint colour all of which have different characteristics