impasto technique: how to build thick, textured paint in oils

Learn where to load thick oil paint, how to build it over a monochrome underpainting, and how to steer it with brush and knife, using five studied paintings.

8 min read

Impasto is paint laid on thick enough to stand up from the surface and keep the mark of the brush or knife. It works by contrast: heavy paint in a few places reads as light and weight because the rest of the picture is thin. There are two traditions. The old oil-painting manuals tie impasto to a particular order of work, with solid white loaded over a monochrome underpainting and thin colour painted over it [1][2]; this is the Van Dyck and Rembrandt method, and it is the one the manuals teach. The other is the direct method of Van Gogh and the painters who followed him, where full-strength colour goes down thick in one session and is never glazed. This guide teaches the first, because it is the one you can learn by stages, and it uses the second as a comparison. It covers the order of work, where the thick paint belongs, how to steer it with the stroke, and five paintings where you can see it at work.

What you need

Stiff white paint, used firm and loaded rather than thinned [1].
A varnish-type medium, added to the white for the thick passages [1].
A full brush for loading paint, and small brushes for touching it in solidly where the lights fall [3][4].
A firm bristle brush that can drag through stiff paint without folding [5].
A palette knife, for laying on broad slabs and for the extra touches in loaded passages [3].
Brown or grey paint for the monochrome underpainting [1][3].
A thin, golden glazing medium for finishing, if you want a unified warm surface over the dried work [3].
A primed canvas or panel that is firm enough to take heavy strokes without flexing.

Step by step

Draw the subject and lay it in as a monochrome, in brown or grey. Keep the shadows warm [1]. This first laying-in is the grisaille, and it carries the form so the impasto does not have to [3].
Squint at your subject and mark the few places that deserve thick paint. The manuals load it on the forehead, the nose and similar high points of a head [1]. Keep the big shapes in view and resist spreading texture across the whole picture [5].
Leave the shadows thin. The shadows of the first laying-in can stay transparent in places, and the thick paint then sits only in the lights [4].
Mix your white stiff, with a little varnish medium, and load it onto the chosen areas [1]. Use a full brush and a generous amount of paint [3].
Place each stroke and leave it. Touch the paint in solidly with a small brush [4]. Every extra pass drags the ridges flat, so aim for the stroke you want the first time.
Use the knife where you want a broad, flat-topped plane of thick paint. Palette-knife strokes that follow the form can build a chunky, solid shape, and a knife can be used alongside the brush in the same loaded passage [3].
Let the impasto dry, or nearly dry, before you colour it [1]. Then paint thinly over the whole area so the colour sits on the relief and the white shows through it [1].
If you want a unifying warmth, float a thin golden glaze over the whole once it is fully dry [3].

Where the thick paint belongs

Impasto is a way of showing light, so put it where the light is strongest. The Dutch and Flemish examples in the manuals place it in the lights of a face while the shadows stay transparent [4][5]. One of the Rembrandt heads the manual describes has varnish impasto on the nose and cheek, with the shadow cast by the cap kept transparent [5].

The paintings in the study list below follow the same rule. In the Robinson record the thick paint is concentrated in the most luminous areas, and the figure is handled more flatly, with less textural emphasis. In the Achenbach record the thick paint is the white of the wave foam, set against nearly black rocks and water. Plan this before you load a brush. Squint at your reference, find the lightest group, and reserve the heavy paint for it.

Let the stroke follow the form

Thick paint holds its stroke direction, so the direction is part of your drawing. A useful rule from the drawing manuals applies to brushwork too. Strokes swinging round a form suggest fullness and foreshortening, strokes across the form suggest softness, and strokes running down the form suggest hardness and toughness [6]. Before you load the brush, decide which of these you want. A cheek built with strokes that turn around it reads as round. A tree trunk built with strokes running down it reads as hard [6].

The example records show the same habit. The wheat in the Van Gogh is built from vertical and diagonal strokes that follow the stalks while the paths curve through it, and the water in the Achenbach study is painted in loose strokes that follow the motion of the waves.

Solomon has a warning that belongs here. Rembrandt's loadings were bold, but the manual says that raw white thrown at the canvas as a make-believe for sunshine and trowelled over the whole surface is not what Rembrandts are made of, and that impastos only answer their end as accents or rare variations from the general level, in proportion to the scale of the work [5]. The direct painters broke that rule on purpose, and if you follow them you need to know you are doing so.

Common mistakes

Thick paint everywhere. When every area is heavy, nothing reads as a highlight. Compare the Robinson figure, handled flatly, with the loaded passages around it, and the thin shadows in the Dutch manual examples [4].
Heavy shadows. The shadow side of a form stays thin, and may stay transparent [4]. Thick, opaque darks lose the contrast that makes the lights stand out.
Thinning the white. The manual calls for stiff white loaded with a varnish medium [1]. Runny white sinks into the underlayer and leaves no relief.
Blending the strokes smooth. The Van Gogh record lists overworking the paint and losing the texture as the first pitfall, and warns against making the strokes uniform or muddying the colour by overmixing. In the Klimt record the dabbed and stippled texture of the foliage is described as essential and should not be smoothed out.
Colouring wet impasto. Thin colour goes on when the white is dry or nearly dry [1]. Working into it too soon drags the relief and muddies the colour.
Using impasto to avoid drawing. The manuals build the form first in a monochrome, and the thick paint is placed on top of that structure [1][3]. Texture over a weak value plan only looks busy.
Losing the big picture. Rembrandt's full loadings were bold, but the manual says to keep the big things in view and keep the planes simple [5].

Study these paintings

wheatfield-with-crows-by-vincent-van-gogh: This is the direct tradition, included for contrast with the manuals' method. The record has the sky blocked in with broad horizontal strokes of blues and white, the wheat painted in vertical and diagonal strokes of cadmium yellow and yellow ochre, and texture then layered into the wheat with lighter yellows applied as impasto. The paths are laid with curved strokes that follow their turn, and the crows are quick black marks put down last. Notice that even here the thickest paint sits in the lightest, most active passage, the wheat, and not evenly across the picture. The record's pitfalls, overworking, uniform strokes and overmixing, are the same faults the manuals warn against.

house-at-saint-tropez-by-albert-marquet: Look for hints of palette-knife application in the thick paint at the roof overhang. The handling is loose, with broad directional strokes that define form without detail, and the surface stays active rather than smooth. Note that hard edges appear where value or temperature shifts abruptly, and soft edges in the sky and distant elements, so the thick passage sits among edges of different strengths.

norwegian-coast-by-moonlight-by-andreas-achenbach: This is the clearest example of impasto serving light. The record describes nearly black rocks and water with almost no middle values, and the wave foam applied in thick impasto that catches light. The moon glow and clouds are soft and feathered, made by blending wet paint, so the thick foam stands out against smooth surrounding areas. Study how the water strokes follow wave motion.

autumn-sunlight-by-theodore-robinson: The palette knife is visible throughout the foliage and ground, and the thickest impasto is built up in the most luminous areas. The lightest lights are the sunlit patches on the forest floor, so the heavy paint and the brightest values coincide. Compare this with the small figure, which is handled more flatly and with less textural emphasis. The colour is placed as separate dabs and short strokes rather than blended.

water-castle-by-gustav-klimt: Look at the foliage, where the record describes thick paint with visible impasto and individual brush marks, built from dabbed and stippled strokes layered on top of one another. The ivy edges are soft and feathered, and the texture is called essential to the painting. Note also that the castle walls have relatively hard edges with clean definition between architecture and windows, so the textured and the crisp areas are clearly separated.

Sources

The Practice of Oil Painting (Solomon J. Solomon (1910)), THE FLEMISH SCHOOL
The Practice of Oil Painting (Solomon J. Solomon (1910)), PREPARED AND DIRECT PAINTING COMPARED
The Practice of Oil Painting (Solomon J. Solomon (1910)), THE DUTCH SCHOOL
The Practice of Oil Painting (Solomon J. Solomon (1910)), THE DUTCH SCHOOL
The Practice of Oil Painting (Solomon J. Solomon (1910)), THE DUTCH SCHOOL
The Practice and Science of Drawing (Harold Speed), SET OF FOUR PHOTOGRAPHS OF THE SAME STUDY FROM THE LIFE IN DIFFERENT...