The History, Definitions, and Techniques of Oil Painting 

with emphasis on its development in the 15th century


From the time of the Greeks the chemistry of art and the chemistry of medicine were closely related and the recipes used for both were frequently written in the same books. These recipes were kept throughout the early centuries of Christianity by monks until their broader use outside of the monasteries in the middle ages. The use of drying oils is recorded among these recipes, listing walnut oil, poppy oil, hempseed oil, castor oil, and linseed oil as varnishes to seal pictures and protect them from water. Adequately thickened, they became resinous in and of themselves and therefore worked as varnishes quite well. Later on, yellow pigments were added to the oil and it was spread over tin foil to mimic the look of gold leaf, but at less cost. And as early as the thirteenth century oil was used for painting details over tempera pictures. Cennini describes the preparation and use of oils in painting on all surfaces.

Oils were purified and bleached in the sun, and drying time was decreased by the addition of metallic oxides such as Litharge or White Lead. Other methods of preparing oil by boiling and mixing with various substances is recorded throughout the middle ages, into the Renaissance, and beyond.

The procedures involved in making a usefully fluid medium with which to paint entire pictures in great detail were perfected by the brothers Van Eyck in the first half of the fifteenth century. From these Flemish artists and their students it is rumored that the new methods were spread to Italy by Antonella da Messina where, "once adapted to Italian taste, subjects, and dimensions, (the new way of painting) was received with enthusiasm."

Alla Prima Painting Painting, usually from life, in a direct manner: Completing a painting in a single session or while the paint is still wet. In past eras used primarily as a means of sketching, but which became a means of producing finished works of art by the impressionists.
Chiaroscuro A method of painting that represents boldly contrasting lighting, usually drawing highlights out of a dark scene. Also an element of this effect in any picture.
Chroma The degree of brilliance of color away from neutral value. [color saturation]
Double Ground Two superimposed paint layers of distinct color covering a sized panel or canvas as a surface upon which to paint.
Fat Containing a large amount of oil
Fat-Over-Lean The rule of painting in layers in which each successive layer of paint should have more oil than the preceeding layer. By increasing the oil content, top layers have increasing degrees of flexibility, reducing the risk of cracking or flaking.
Gesso Gypsum (calcium sulphate) mixed with animal glue and applied as a ground to a wood substrate. Used in Southern Europe (primarily Spain and Italy). Northern Europeans used a similar ground of chalk (calcium carbonate) in a glue binder.

A first, coarse layer was known as gesso grosso. While a smooth top layer which could be polished to a fine tooth was called gesso sottile. Some later artists applied only one layer of gesso sottile.

Glaze A film of transparent color laid over a dried underpainting.
Grisaille Monochromatic painting usually in various tones of gray. Traditionally the underpainting of a work, where local color is applied over the grisaille as opaque, semi-opaque or transparent color. Often shadows are colored with transparent colors and highlights are built up with increasing thickness of opaque paint.
Ground The primary surface on which color is applied. Usually refers to an opaque coating rather than the support. Traditionally opaque white oil priming on canvas and chalk or gypsum mixed with animal glue (gesso) on wood panel. White acrylic polymer can be used on either surface.

If a colored isolation layer (imprimatura) is used as the primary surface, it can be considered the ground. (see also "Toned Ground")

Highlight The lightest tone in a painting.
Hue The simple color of a substance, for example: red, bluish red, or yellow-red.
Impasto Painting thickly with a bristle brush or palette knife in order to create surface texture.
Imprimatura An isolation layer consisting of pigments bound in an oil medium and applied over chalk or gesso grounds to prevent the medium in the subsequent paint layers from being absorbed by the ground. Could be bright to dark, transparent or non-transparent. Color provides a middle tone from which one can quickly move between lights and darks to produce a full value painting. Should be mid-tone or lighter -- extremely dark underpainting can show through top layers as the work ages, especially when using lead white.

In modern usage on oil primed canvas, "imprimatura" is often used to describe a transparent stain of oil color that is applied to the entire surface to create a unifying midtone.

Most common colors: brown, earth-red, grey, or grey blue.

Lightfast Resistant to fading when exposed to sunlight. Absolute measurement in artists' pigments; relative measurement when applied to industrial coatings applications. Example: a ten-year house paint would be considered lightfast if it resisted fading for ten years. Artists' pigments are judged in terms of centuries.
Local Color The true or actual color of an object
(as compared to the color effect it produces when viewed as part of a whole composition or when influenced by light or atmospheric conditions in nature or by the technique and intentions of the painter in a work of art.)
Medium A liquid additive used to control the application properties of paint, its drying time, and the elasticity of paint film when dry. In oil painting this usually contains combinations of drying oils, varnishes, balsams, essential oils or solvents, and driers.
Modeling Indicating the three-dimensional form of an object by the appropriate distribution of different tones. Creating the illusion of volume by painting the effects of light and shadow on form.
Monochromatic Underpainting A preliminary painting in tones of one color. Overpainted with transparent, semi-opaque, and / or opaque color. See Grisaille above.
Palette The implement upon which a painter holds or mixes his colors. Or a selected assortment of colors chosen for use in a painting technique.
Pentimento The visibility of line or color through the increasingly transparent overpainting which was originally used to conceal it. Ghost image. A characteristic of linseed oil since its refractive index increases with age.
Polymerization An internal molecular realignment brought about by external force which changes the properties of a substance and increases its molecular weight without the addition of any new ingredients.
Example: the external force of oxygen upon a drying oil.
Prime / Primer To cover a surface with a preparatory coat of color. A first coat or layer of paint, size, etc., given to any surface as a base, sealer, or the like. Often used to describe a pigment and oil (paint) ground applied to cloth such as canvas or linen. (see "Ground" above).
In 15th century Europe, the guilds of St. Luke recognized the profession of the panel maker as an independent craft within the guild. Artists could purchase panels "primed and prepared" with an imprimatura from such workshops, eliminating this slow and dirty job from their studios.
Scumbling Scraping or scrubbing or dragging a thin layer of lighter opaque or semi-opaque color over a dark underpainting with a bristle brush, allowing the underpainting to show through.
Tone The degree of lightness or darkness of a color.
Toned Ground Where color is mixed with white as a primer to provide a uniform opaque ground.
Underpainting Preliminary painting, over which successive layers of color are added. Can be monochrome or colored.
Value Degree of lightness and darkness.
Varnish Protective surface film imparting a glossy or matt surface appearance to a painting.
Vehicle The liquid into which a pigment is ground in order to turn the dry powdered pigment into a liquid paint. The carrier of pigment.
Verdaccio Greenish underpainting


Notes from Methods and Materials of Painting of the Great Schools and Masters, Vol. 1, (formerly titled: Materials for a History of Oil Painting) by Sir Charles Lock Eastlake, one-time President of the Royal Academy of England. Originally published in 1847. Republished by Dover Books 1960. [Currently out of print.]

Definitions and technical information also acquired from The Random House College Dictionary, Revised Edition;

The 1999 WorldBook Encyclopedia CD-ROM;

The Artists' Handbook, the complete practical guide to the tools, techniques and materials of painting, drawing and printmaking
by Ray Smith (ISBN 0-394-55585-6)

The Painter's Guide to Studio Methods and Materials by Reed Kay (ISBN 0-13-647941-3 and 0-13-647958-8) [currently out of print]

Artists' Handbook of Materials and Techniques
by Ralph Mayer, 5th Edition, Revised and Updated.
(ISBN: 0-670-83701-6)

Artists' Pigments:
A Handbook of their History and Characteristics Vol. 1

Robert L. Feller, Editor. Published by the Cambridge University Press in cooperation with the National Gallery of Art, Washington D.C. (ISBN 0-521-30374-5, and 0-89468-086-2)

Industrial Organic Pigments:
Production, Properties and Applications

W. Herbst and K. Hunger (ISBN: 3527288368)

Looking Through Paintings:
The Study of Painting Techniques and Materials in Support of Art Historical Research.
Editor: Erma Hermens - Associate editors: Annemiek Ouwerkerk and Nicola Costaras. 1998
(ISBN 90 6801 575 3 and 1 873132 56 5)

And through phone discussions with representatives of pigment manufacturers Ciba Specialty Corp. and Engelhard Corp.,
Ron Harmon, paint chemist for Daniel Smith Artists' Materials of Seattle, WA
Chemistry professors at Indiana/Purdue University, Fort Wayne Campus
Mark David Gottsegen, Chairman, Artists Paints and Related Materials, Department of Art, University of N.C., Greensborough, and
Catherine Metzger, Conservator at the National Gallery of Art, Washington, D.C.

History, Definitions, and Techniques | Drying Oils and Mediums
Resins and Varnishes | Pigments Past |Pigment Chemistry
Supports for Painting | Grounds on Canvas | Techniques of Past Masters
Discussion with National Gallery Conservator