What is Plein Air painting? Plein Air painting is when the artist leaves their studio behind and experiences painting and drawing in the landscape. The practice goes back for centuries but was truly made into an art form by the French Impressionists. Their desire to paint light and its changing, ephemeral qualities, coupled with the creation of transportable paint tubes and the box easel—the precursor to the plein air easels of today—allowed artists the freedom to paint “en plein air,” which is the French expression for “in the open air.”