Oil painting

• 1. Introduction

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  Oil painting is a process that has shaped more of the world's most celebrated art than almost any other technique. Somewhere in the caves and carved rooms behind the Bamiyan Buddhas in Afghanistan, artists working around 650 AD pressed pigments bound in oil into the rock walls. Those murals are the oldest surviving examples of oil painting on earth. They predate European use of the same method by roughly 900 years.

  How did a technique perfected in Asia travel so far and transform art so completely? Who are the artists credited with bringing it to the western world, and what do those claims get wrong? And why, after centuries of refinement, does a single decision about which oil to use still change what a painting looks like today?

• 2. Origins in Afghanistan

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  Bamiyan sits along the ancient Silk Road, a settlement known for colossal stone Buddhas carved directly from the cliffs. Behind those statues, rooms and tunnels were cut into the rock, and it is on the walls of those rooms that Buddhist artists left the murals dated to around 650 AD. The artworks display a wide range of pigments and ingredients, and researchers found that the painters even applied a final varnish layer over the finished work.

  The level of technical refinement visible in these murals suggests that oil-based painting had been practiced in Asia for some time before that century. No equivalent technique existed in Europe at the time. It would take roughly 900 more years before European painters independently arrived at a similar method.

• 3. Europe Arrives Late

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  A monk named Theophilus Presbyter, sometimes identified as Roger of Helmarshausen, wrote a treatise called De diversis artibus around 1125, and in it he gave instructions for painting with oil-based media. At that stage in Europe, the technique was applied mainly to sculptures, carvings, and wood fittings, with a particular advantage for outdoor surfaces. Shields used in tournaments and decorative shields hung on walls both lasted longer when painted in oil than when coated in traditional tempera.

  Cennino Cennini also described the oil technique in his Book of Art. Most European Renaissance writers, including Vasari, falsely credited northern European painters of the 15th century with the invention of oil paints. Jan van Eyck was the name most often named. What van Eyck and his contemporary Robert Campin actually did was something distinct from invention: they were the first to make oil the regular painting medium and to systematically explore the possibilities of layering and glazes. The rest of Northern Europe followed, and then Italy took up the approach as well.

• 4. Canvas, Copper, and the Move from Wood

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  Early oil paintings were almost entirely done on wooden panels, which required seasoning and an expensive multi-step preparation process. The panels themselves were assembled from several pieces of wood and had a tendency to warp. Rubens still painted large works on wood well into the 17th century.

  Canvas began to replace wood toward the end of the 15th century. It was cheaper, easier to move, and capable of supporting larger compositions without the weight problem that made oversized panels impractical. Venice led the transition, partly because sail-canvas was readily available there. For smaller works demanding very fine detail, artists turned to copper plates, often reusing printing plates from printmaking. These metal supports were more expensive but provided a surface firm enough to hold intricate work. By 1540, tempera had become all but extinct as a method for panel painting in most of Europe, though Italians kept chalk-based fresco for wall paintings, which performed better than fresco in damp northern climates.

• 5. The Fat Over Lean Rule

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  Traditional oil painting often begins with a charcoal sketch or a drawing in thinned paint directly on the canvas. The governing principle for applying layers is known as "fat over lean": each successive layer of paint must contain more oil than the one beneath it. Reversing this causes the finished painting to crack and peel as it ages.

  Old masters built their images through thin, almost transparent layers called glazes, applying each one and waiting for it to dry before adding the next. The underpainting beneath these layers was usually white, often gesso primed with white, so that light could pass through the translucent glazes and reflect back outward. This approach gave oil paintings their characteristic luminous quality. Van Eyck and Campin sometimes broke from this waiting period, using a wet-on-wet technique in places, painting a second layer before the first had dried. Giovanni Bellini, a Venetian painter working around 1500, was among the earliest to employ impasto, a raised or rough surface texture that drew visible attention to the physical act of painting.

• 6. Plein Air and the Metal Tube

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  Before the 19th century, artists or their apprentices ground pigments by hand and mixed paints fresh before use. That requirement kept painting largely inside studios, since transporting the materials was cumbersome. An American portrait painter named John Goffe Rand changed that when he invented the squeezable, collapsible metal tube in 1841. Pre-mixed paint in tubes made it practical for artists to work outdoors, loading their colors and heading out into the landscape.

  This convenience became central to French Impressionism, which treated plein air painting as a defining approach. Working outside also created a new technical pressure: there was no time to wait for one layer to dry before applying the next. This pushed painters toward the alla prima method, meaning the entire image was completed in a single session with wet paint laid over wet paint. Several contemporary artists now combine the two approaches, using wet-on-wet for bold color passages and glazing for depth.

• 7. Oils, Pigments, and Chemistry

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  Linseed oil is the most widely used of the drying oils, coming from the flax seed, the same plant that produces linen canvas. Safflower, walnut, and poppyseed oil are sometimes chosen when mixing lighter colors like white, because they yellow less on drying than linseed. The trade-off is that they dry more slowly and may produce a weaker paint film over time.

  Lead white dominated as the primary white pigment for centuries, prized for opacity and fast drying. Lead-tin yellow was used by Pieter Lastman and other painters of the Dutch Golden Age. Litharge, or lead monoxide, was historically added directly to drying oils to speed up the drying process. Restrictions on lead compounds in recent decades have curtailed these uses; in the United Kingdom, for example, lead pigments are limited to licensed restoration work. Modern water miscible oil paints now allow painters to clean their brushes with water rather than solvents, a development that addresses both convenience and the toxicity of traditional thinners like turpentine.

• 8. Brushes, Blades, and Texture

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  The finest brushes used in oil painting are made from the tail hairs of the Siberian weasel and are called kolinsky sable. What painters value in these brushes is a quality called "snap": the ability to return to a precise point when lifted from the canvas. Floppy fibers without this quality, such as squirrel hair, are generally avoided by oil painters. Hog bristle brushes serve a different purpose, suited for bold strokes and impasto textures. Fitch and mongoose hair brushes are finer and find more use in portrait and detail work.

  Beyond brushes, painters use flat metal palette knives both to apply paint and to scrape it away. Rags, sponges, cotton swabs, and even bare fingers have all served as application tools. When an artist wants to remove an entire layer, a rag with turpentine can lift wet paint; once the paint has hardened, scraping is the only option. Oil paint dries by oxidation rather than evaporation, and most colors become dry to the touch within two weeks, with some drying in a matter of days. When a finished painting has cured for up to a year, many artists seal the surface with a varnish made from dammar gum crystals dissolved in turpentine, which can later be removed during conservation without disturbing the paint beneath.