A student of John J. Audubon, Baird encouraged young men to become professional illustrators. Even Charles Doolittle Walcott, fourth Secretary of the Institution, prepared and published some of his own illustrations of the famous Burgess Shale fossils, which he discovered in the Canadian Rockies in 1910. By the 1890s, photographic printing was commonplace, and allowed for quick reproduction of either ink illustrations, with lines, stipples, and cross-hatching, or continuous tone, involving graphite, carbon dust, and charcoal. But this new kind of printing never really replaced illustration. Photographs, while useful, cannot reconstruct, simplify, or delineate important details, which depend on an illustrator's interpretation.
Illustrations are more informative, especially with microscopic subjects.
Around the turn of the century, several illustrators were in the employ of the National Museum. Notably, botanical art was open to women even when higher education was not, and more than one woman began her science career by illustrating specimens and then taking on research. One such woman was Mary Agnes Chase, who worked by day as an illustrator for the U.S. Department of Agriculture and by night in the National Museum herbarium. After 30 years, she became a senior Smithsonian botanist in charge of the collection of grasses. By the 1960s, the National Museum of Natural History employed several full-time illustrators, and many others who lived nearby worked for the museum as contract artists.