You don't see it too often but from time to time, in the right location and circumstances, one might find an artist sitting at his easel painting some picturesque landscape or interesting old building. The scene of the artist at work out-of-doors is, in itself picturesque. I've included images of artists painting outdoors in more than a few landscapes, in one case even a self-portrait. However I must confess, I was working from a photo and in fact, I've never painted outdoors in my life. I will sometime though, when I can overcome my addiction to air-conditioning. Even though it's not as common as it once was, painting, as the French called it, "en plein air" still has a certain charm and novelty to it even though today, it may sometimes be over-hyped and somewhat gimmicky.
The French though, made a fetish of it, starting with what's called the Barbizon School in the mid 1800s and then especially as the Impressionists journeyed off to the Normandy Coast or to the forests of Fountainbleu. (Claude Monet even went so far as to have a boat built so he could paint water from the water.) Painting outdoors caused art to change. First of all paintings became smaller. One could hardly cart and 8-foot by 10-foot canvas with supporting easel through the streets of Marlotte just to paint a bunch of trees. Not only that, such a large landscape painting would have been unbearably pretentious, looking more like theatre scenery. Easels too had to change. They became smaller and portable. They still had to be sturdy and adjustable, but light enough that an artist could hike deep into the woods to find just the right spot to set up and work.
He needed a box, large enough to carry his oils, brushes, palette, tubes of paint, brush cleaners, knives, lunch, maybe a little wine, and especially wet paintings after the day's work. It also needed to be sturdy, custom-built, and have a comfortable handle. A folding campstool was a must for all but the most athletic. And one had to learn to paint fast, capturing the changing light quickly and faithfully, or else one might spend more time scraping paint off the canvas than applying it. And most of all, one had to accept a new standard of beauty, where nature and colour ruled, where all things existed only insofar as they reflected light. It was not easy, throwing off centuries of artistic sensibilities so ingrained they were more instincts than teachings, but "en plein air" demanded it, and a whole new way to paint was born.