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Fat Over Lean Oil Painting Technique

Suganya Sukumar
Fat over lean method is a technique that is applied for making oil paintings. Artists use this technique to give a realistic beauty to their paintings. Here is some information about this technique, that will surely help you to make your own exquisite painting.
The discovery of oil painting is a boon for artists and fine art lovers. Before the advent of this form of painting, a pigment called tempera, was used in paintings. Tempera is produced by using glutinous substances such as egg yolk and size, which are water soluble. Linseed oil, which is made from the seed of flax, was mixed with tempera.
Turpentine is used to dilute the paint and mediums used in the paintings. It is a traditional liquid that emits a kind of noxious smell. Solvents such as gamsol or turpenoid are added with turpentine to suppress its strong odor. Brushes are frequently cleaned using these solvents too.

Fat Over Lean Principle in Oil Painting

  • The basic thing about fat over lean technique is, paint coatings are done layer by layer. The lower layer should have a thinner coating than the upper layer.
  • Instead, if the upper layer is made thinner than the lower layer, the upper one will dry up faster and cause cracks in the painting. This is called alligatoring.
  • Gain sufficient knowledge about the proportion of solvent and medium, which you need to maintain for your paintings, because, these factors decide the drying time of the paints that you use.
  • If a lean layer is made over a fatty layer, it will cause a whitish haze on painting surface after some days. This is called blooming and this effect cannot be removed.
  • The first layer of your painting should be a mixture of paint and a solvent (lean mixture). Mixture of solvent and linseed oil should be the next layer and the last layer should have more linseed oil content mixed with the paint solution.
  • Use a good quality oil to avoid yellowing or darkening of your paintings, and also avoid too much oil in your painting, so as to prevent wrinkles after the painting gets dried up.
  • The final thing is, protective coating should be given, so as to give a final colorful look to your painting.

Drying Speed of Paints

  • Quick Driers: Flake white, raw umber, burnt umber, cobalt green, cobalt blue, cobalt violet, manganese blue, Prussian blue, Naples yellow, aureolin yellow, Indian red, Venetian red, etc.
  • Average Driers: Raw Sienna, mars colors, chromium oxide, zinc yellow, strontium yellow, viridian green, quinacridone red, quinacridone violet, ultramarine violet, etc.
  • Slow Driers: Earth colors, cadmium colors, cerulean blue, vermilion, ultramarine blue, hansa yellow, zinc white, titanium, ocher, permanent green, alizarin crimson, etc.
  • Very Slow Driers: Ivory, lamp, Vandyke brown, emerald, etc.

Oils Used in the Paintings

  • Linseed oil is used in two forms. They are sun-thickened linseed oil (oil exposed to air) and refined linseed oil (slow drier).
  • Stand oil, which is a polymerized form of linseed oil, is of better quality than the normal linseed oil.
  • Walnut oil delays yellowing, but it turns rancid if not used fresh.

Mediums Used in Fat Over Lean Technique

The medium is the oil, that is mixed with the paint, to make it transparent or matte. The medium decides the drying time of the paint too. There are various types of mediums that decide the look of your paintings
  • Standard Medium consists of linseed oil, resin and turpentine. Addition of standard mediums to the paints give different qualities, such as dryness, durability or flexibility.
  • Glazing Medium is used in the process of glazing, which is done by diluting a transparent color with the paints. The property of transparency allows you to view two different colors at the same time.
  • Drying Medium influences the drying time when mixed with the paint. Synthetic resins which are known as alkyds are used to speed up the process of drying. These driers should be used carefully, as they can spoil the painting by causing cracks or crazes.
Many artists used the aforementioned technique for producing beautiful paintings. Art should never be compromised, otherwise, the effort made or value of the art will not be recognized. Using fat over lean technique will make the painting more beautiful, lively and durable. Employing this technique is surely not a very easy task, and it requires a good artistic talent and adequate practice of using the paints.