Impasto: painting with texture and thick oil paint

Impasto means laying paint on so thickly that the mark of the tool stays visible on the surface. The paint is no longer just a carrier of colour: it becomes a material that stands out from the canvas and casts its own small shadow.

A painting that changes with the light

This is the main consequence of a thick layer. A few millimetres of relief are enough to make the picture look one way in the morning and another under a lamp in the evening, and the texture comes alive most when light falls from the side. It is worth checking where the light comes from before choosing a wall for such a painting.

What it is applied with

• A painting knife — flat patches with sharp, clean-cut edges.
• A stiff bristle brush — parallel furrows left by the hairs, good for grasses and stalks.
• Paint straight from the tube — the heaviest mark, and the slowest to dry.

Where it makes sense in nature motifs

A thick layer describes well the things that stand out in nature too: flower heads, tufts of grass, bark, points of light across a meadow. I usually keep it for the end and for a few places only. A canvas covered in impasto throughout loses its hierarchy and the eye has nowhere to settle.

What to watch out for

A thick layer dries from the top and stays soft under the skin for a long time, so the painting should not be wrapped or varnished too early. It also has to go over a fatter layer, never over a lean underpainting, or it will crack in time. Transport is safer flat, because the highest ridges of paint rub off easily.

A strongly textured painting rarely needs an elaborate frame — I wrote about that in how to choose a frame for an oil painting. The oils themselves are in the paintings gallery.