The landscape artist cannot understand the complexity and character of an outdoor scene without painting on location, or, as the French Impressionists who popularized this genre, by painting "en plein aire."

Before small, resealable paint tubes were invented, carrying one's supplies into the field was a cumbersome and messy process so most landscapes were painted in a studio. Photographs are a wonderful reference but cannot capture the subtle effects of nature that can be appreciated from direct observation.

Plein air paintings can be finished pieces or small, quick sketches or studies used to gather information for a larger studio painting and not for sale or display in a gallery. Plein air paintings have their own charm as they are usually created in one session to minimize the problems of changing weather and lighting conditions.