“By the fifteenth century, paper mills had been established in Europe to meet the demands created by the increase in printing that resulted from the development of movable type. It was the availability of paper and the use in Italy, at about the same time, of the black chalk often referred to as Italian or black stone that brought about the birth of drawings as we know it today. The chalk, a soft natural carboniferous slate that could be cut into strips, gave to drawing a freedom and tempo that was not easily attained with the more traditional pen and ink or metal points. In addition to black chalk, red chalk (originally, hematite), ranging in color from a violet red to an orange red and often referred to by its French name, sanguine, became popular in the sixteenth century. White chalk (steatite or gypsum) was used either to highlight black- or red-chalk drawings or to prepare the tinted grounds on which the drawings often appeared.”

—Joseph H. Krause, The Nature of Art, 1969.