Plains Indian drawings and historical records produced in the nineteenth and early twentieth centuries made progressively greater use of nontraditional drawing materials such as commercial colored pencils, crayons, ink and watercolors. Similarly, cloth and paper begin to supplant traditional hide supports during this period. These non-traditional materials rarely have been studied in this context, yet their dates of manufacture and subsequent availability through traders and missionaries, or distribution by the Bureau of Indian Affairs, has the potential to inform about the creation date of a drawing or historical record. An analysis of the materials and methods used to produce the Rosebud winter count, a Lakota pictographic calendar, is described. Results indicate that the 136 motifs on the Rosebud winter count were produced, likely in sequence, by two different hands, followed by general outlining and finally, motif numbering. The materials used in the winter count were for the most part unavailable before the nineteenth century. Colored pencils containing the pigment Prussian blue was found to form an integral part of the winter count, thus allowing the dated of manufacture to be placed most likely after 1883.