Invented during the Renaissance, the noble oil technique is widely used today.
Made from pigments finely crushed in linseed or poppy seed oil, it comes in a paste which can be worked with a metallic spatula (knife painting) or with a stiff brush.
It is possible to dilute the paint and then apply with a soft brush.
Its main characteristics are its brightness, the enamelled effect and luminosity of the composition, the drying time which allows ample reworking, and its resistance to humidity.
Many mediums can be added in order to change its characteristics: siccative and structure etc. It can be diluted with essences (vegetable or mineral).
When layering it is imperative to respect the rule of “fat on lean” the first layer is diluted with a little essence and referred to as lean; the second a little less diluted and finally a layer which contains only the oil. Failure to follow this procedure will result in cracks within a few months.
It is advisable to paint on materials (canvas, wood, paper) primed with a special preparation to improve the adherence of the paint while limiting the absorption of the oil. This will conserve the brightness of the painting and allow for lengthy reworking while protecting the support from damage caused by the oils and solvents.
One of the most current primers is Gesso, also suitable for acrylic paints and which can be applied to heavy watercolour paper.