Types of Paints

Oil Paint

• The vehicle and binder: plant oils; most common linseed oil extracted from the seeds of the flax plant (oiticica oil, safflower oil, poppy-seed oil, perilla oil, tung oil).
• The viscosity of the paint may be modified by the addition of a solvent such as turpentine or white spirit (mineral spirit), and varnish may be added to increase the glossiness of the dried oil paint film. 
• Oil paints have been used in Europe since the 12th century for simple \n decoration, but did not begin to be adopted as an artistic medium until the early 15th century.

Acrylic Paint

• Acrylic Paint binder: polymerized material, ground up and suspended in water (water emulsion), process introduced in 1956.
• Acrylic paint: a fast-drying paint made of pigment suspended in acrylic polymer emulsion and plasticizers, silicon oils, defoamers, stabilizers. 
• Acrylic paints are water-soluble, but become water-resistant when dry.
• Depending on how much the paint is diluted with water, or modified with acrylic gels, mediums, or pastes, the finished acrylic painting can resemble a watercolor, a gouache or an oil painting, or have its own unique characteristics not attainable with other media.

Tempera Paints

• Tempera: a permanent, fast-drying painting medium consisting of colored pigments mixed with a binder medium, usually glutinous material such as egg yolk, or any other oil medium.

• Tempera paints: oil-based paints which can be diluted with water and which form an insoluble film on drying. 

• Unlike in oil paints, tempera paints use oil as the binder, but the oil is homogeneously mixed with water to form an emulsion. 

  • Formation of such emulsions require the presence of an emulsifier or stabilizer.

  • Emulsions: stable mixtures of two immiscible liquids distributed uniformly in each other.  Formation of such emulsions require the presence of an emulsifier or stabilizer.

  • Emulsifier: usually a long molecule that is partially ionic at one end, so called head (so this end dissolves well in water) and molecular with only covalent bonds in the rest of the molecule (so this part dissolves well in oil).

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• Tempera paintings are very long-lasting, and examples from the first century AD still exist. Egg tempera was a primary method of painting until after 1500 when it was superseded by the invention of oil painting. 

Water Colors and Gouache Paints

• Water colors: made from very finely ground pigments suspended in water, usually with gum Arabic serving as a binder.

  • Particles of pigments become embedded in the paper and adhere to it.
  • Water colors use basically the same pigments as oil paints.

• Gouache paints: opaque water colors. 

  • The proportion of pigments to paint vehicle is much greater (sometimes up to 50% of the paint is the pigment – expensive!). 

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