Elizabeth Moutal, American, active c. 1935, Mortars and Pestles, 1937, watercolor over graphite
	Albert Rudin, American, active c. 1935, Roller Skates, 1941, watercolor with white heightening over graphite

The task assigned to Index artists was to make completely accurate illustrations of folk, popular, and decorative art that other Americans might consult in their search for a national vocabulary of design. Ironically, while compiling pictorial resources from which modern artists and designers might derive inspiration, the Index artists had to resist engaging in the very kind of creative interpretation their work was meant to stimulate in others. They had to produce documentary-quality images that conformed to a format suitable for publication in the portfolios. Despite these constraints, many of the watercolor plates are outstanding works of art in their own right: they have an uncanny power to make one see the depicted objects with unaccustomed clarity, to discover at a glance details and characteristics normally perceived only through prolonged study. To achieve this intense verisimilitude, the artists would minutely observe and contemplate the tactile qualities of the surface, its luminosity, and its subtle gradations of color, texture, and form, and then combine and translate all this optically, intellectually, and sensuously acquired data into perfect two-dimensional facsimiles.

Isadore Goldberg II and John Tarantino, Americans, both active c. 1935, Stoneware Jar, 1941, watercolor over graphite

While adhering to the prescribed Index format--for example, not depicting backgrounds and using shading only within the object to show its form and texture--the artists still were able to make subtle aesthetic choices. Elizabeth Moutal artfully arranged pestles in their mortars to enliven and balance her rendering, and Albert Rudin posed a pair of roller skates and manipulated their straps in a way that both heightens the illusion of depth and creates a most satisfying composition. Technical choices also varied. Some artists would let the pigment flow freely from their brushes to simulate, for example, the effect of blue slip puddled on a stoneware jar; others, such as Mae A. Clarke, preferred to exercise tighter control. Although it may seem difficult at first to distinguish the work of one Index artist from that of another, a closer look indicates that the drawings are as distinctive as handwriting.