Perhaps the most important legacy of tube paints was that they allowed artists to become more mobile, setting up their easels in a country meadow or on a seashore. The mobility of tubes meant that artists were free to work “en plein air,” or in the plain air. Painting outside their studios allowed artists to capture subtleties of light that are so characteristic of Impressionism. As Renoir said, “Without tubes of paint, there would have been no Impressionism.” According to the passage, the greatest advantage of using paint tubes was that they gave artists ____