Tonalism emerged as an artistic style -- or perhaps a convergence of styles -- around 1880, though the term "tonalist" wasn't used until the 1890s.

Though the Tonalist style was most obvious in America, it was influenced by French paintings from the Barbizon school and Luminism, as well as Hudson River School landscapes.

Tonalist art is sometimes described as dark and moody, and can reflect a palette of cool or grey colors. However, the skies and both the reflected and local color can be warm and romantic, similar to the Luminist school of art.

It may by simplest to define 19th-century Tonalism by what it was not: Tonalist artists generally avoided the high-keyed palettes and color combinations of the Impressionists. Many Tonalists also worked with thin, sometimes transparent layers of paint, revealing few brushstrokes in the finished work.

Early Tonalist artists often followed one of two trends. One is the softer style represented by George Inness and the French Barbizon School. These landscapes can include precise details and broad expanses of sky, carefully painted to capture the lighting. These are by far the most popular Tonalist works.

The other Tonalist approach is exemplified by James McNeil Whistler, whose style is sometimes described as Aestheticism. This work was heavily influenced by Whistler's study of Japanese art, and focused on simple compositions and a limited palette, with the free use of black for drama.

Whistler's clearest examples of Tonalism are his "Nocturnes" series. They were partly influenced by Whistler's fascination with tone, but also the principles of Horace Lecoq de Boisbaudran.

In the late 1840s, Lecoq had published the popular 1848 pamphlet, L'Education de la mémoire pittoresque (The Training of the Memory in Art), encouraging artists to study the subject but then draw or paint from memory.

The technique of working only from memory is still popular among modern Tonalists, and -- along with the emphasis on a limited palette and simple compositions -- remains one of the most distinguishing aspects of this style of art.

[Illustration: Nocturne: Blue and Gold, by James McNeil Whistler, 1877.]