En Plein Air /on plen AIR/

The French phrase means simply 'in the open air', and it names the practice of painting a finished or near-finished picture out of doors before the motif, rather than working up a studio composition from sketches and memory. The aim is fidelity to the fleeting conditions of real light — the exact colour of a shadow at a particular hour, the haze over a field, the sparkle of sun on water — that cannot be reconstructed indoors.

Plein-air sketching in oils had been practised by Constable and the Barbizon painters earlier in the nineteenth century, but it became a finished method, and a movement, with the Impressionists. Two practical developments made it possible: the portable box easel and, crucially, the invention of the collapsible metal paint tube around 1841, which freed painters from grinding and mixing their colours in the studio. Monet, Renoir, Pissarro and their circle took their easels to riverbanks, gardens and boulevards and built an entire aesthetic out of the discovery that light, not the object, is the real subject of a landscape.

Painting outdoors imposes its own discipline. The light changes by the minute, so the painter must work fast, with a loaded brush and abbreviated marks — which is one source of the broken, sketch-like surface characteristic of Impressionism. Many painters returned to the same spot at the same hour over many days to finish a single canvas in consistent conditions.

To recognise plein-air work, look for the freshness and accuracy of the light, the quick confident brushwork, and the sense that the picture records a specific moment of weather that will never recur.

Written by Alexander Knigge, Editor, Artifact World Gallery · Further reading on Wikipedia ↗