That en plein air is a French expression which means “in the open air”, and is particularly used to describe the act of painting outdoors?
Artists have long painted outdoors, but in the mid-19th century working in natural light became particularly important to the Barbizon school and Impressionism. The popularity of painting en plein air increased in the 1870s with the introduction of paints in tubes. Previously, each painter made their own paints by grinding and mixing dry pigment powders with linseed oil. It was during this period that the “Box Easel”, typically known as the French Easel, was invented. It is uncertain who developed it first, but these highly portable easels, with telescopic legs and built-in paint box and palette, made treks into the forest and up the hillsides less onerous. Still made today, they remain a popular choice even for home use since they fold up to the size of a brief case and thus are easy to store. One popular version is named the Jullian easel, designed by Roger Jullian, a French prisoner of war during World War II, who devoted himself to designing and later manufacturing the perfect sketch box easel.
While walking around Annisquam the day after the storm, I encountered these two artists painting en plein air, and it was a very chilly plein air at that. Each was painting their view of the Village from opposite sides of the end of Leonard Street. Chris Coyne (first picture), really impressed me by having included me in his painting by the time I reached the top of the rise where they were set up. Chris has a gallery at 37 Bearskin Neck, called Chris Coyne Fine Art www.coynefineart.com. The second artist is Caleb Stone of Ipswich. Caleb’s website is http://calebstoneart.com. Both are very accomplished artists, and it was nice to meet them and impressive to watch them work in the bitter cold with no gloves on. Personally, I’m a wimpy studio painter and you’d never catch me outside painting in the cold like that. These guys are hardcore.
From Wikipedia and The Fox Chase