Oil paint

Oil paint
Used in artistic or decorative painting techniques.

Oil has the advantage of offering a wide range of gloss, transparency and modelling effects. The film formed after drying is very solid and impervious to water.
The disadvantage is that oxidative drying is slow, and there is a high risk of cracking due to the superimposition of layers, each at a different stage of drying. Another disadvantage is that oil paints tend to yellow over time.

Ingredients:

Drying oil (linseed oil, walnut oil, poppy seed oil, safflower oil, hemp oil) as a binder, turpentine to dilute the paint, siccative (to speed up drying), Meudon white (chalk) as a filler, necessary depending on the pigments.

Tools:

equipment for grinding the colours: marble or thick glass plate, palette wheel, palette knife, tube for storing the pigment paste, white spirit for cleaning, gloves.

Substrates:

Oil paint can be applied to any substrate, but cellulose substrates (paper, plant fibre canvases) must be protected by a good sizing. Preparations can be lean, emulsified or fatty.
The ‘fat on lean’ rule ensures that superimposed layers adhere well when drying by capturing oxygen from the air, and prevents cracking. Preparing mediums with oil and waxes or resins in solution (dammar, for example) makes it possible to get round this rule to some extent.

Composition:

27g linseed oil, 80g powdered pigment (e.g. cadmium yellow), Meudon white (optional).
NB: For each type of pigment, the quantity of oil is different.

Recipe:
Place some of the pigment on the marble or glass plate. Pour in a small amount of oil. Mix the oil and pigment with the palette knife. As soon as the pigment begins to set, add a little more pigment. Add the rest of the oil, then the pigment, and mix until you have a smooth paste.
Grind the mixture with the rolling pin on the baking sheet, making circles. The paste will soften as it binds with the oil.

The paste can be stored in aluminium tubes or airtight jars (you can pour water over the oil to prevent polymerisation).

Another recipe for decorative paint:
400 to 600g of pigment, 500g of colourless filler (Meudon white, for example), 1l of oil and 1/2l of turpentine.
Prepare the Meudon white – linseed oil mixture in advance.
Dilute the pigment with a little turpentine to loosen it in a container, then add it to the oil-filler mixture.
Mix well. Dilute with turpentine according to the desired effect (glaze or coverage).

Recommendations:
The more linolenic acid an oil contains, the drier and more yellowing it becomes. Oil is a film-forming material, especially when cooked. It should therefore be diluted with a solvant or thinner before use to avoid peeling. Leaving an oil in a closed jar in the light for several months clarifies it.

Pigments ground in oil and applied have very different hardening times. Prussian blue, umber and ochre dry much more quickly than zinc white or madder lacquer.
Just because a layer of oil colour feels dry to the touch doesn’t mean it’s hard in depth. It is sometimes necessary to wait a year before applying a final varnish to an oil painting.

Manières de peindre, carnets d’atelier, Jean-Pierre Brazs, éditions Notari, 2011.

Peindre à l’huile comme les maîtres, Claude Yvel, Edisud, 2003.

La technique de la peinture à l’huile, Xavier de Langlais, Flammarion, 2018.

La couleur expliquée aux artistes, Fabien Petillon et Isabelle Roelofs, Editions Eyrolles, 2012.