The Hidatsa and other Northwest Indians usually employ a piece of buffalo rib or a piece of hard wood having an elliptical form. This is dipped in a solution of glue, with or without color, and a tracing is made, which is subsequently filled up and deepened by a repetition of the process with the same or a stronger solution of the color.
Of late years in the United States colors of civilized manufacture are readily obtained by the Indians for painting and decoration. Frequently, however, when the colors of commerce can not be obtained, the aboriginal colors are still prepared and used. The ferruginous clays of various shades of brown, red, and yellow occur in nature so widely distributed that these are the most common and leading tints. Black is generally prepared by grinding fragments of charcoal into a very fine powder. Among some tribes, as has also been found in some of the “ancient” pottery from the Arizona ruins, clay had evidently been mixed with charcoal to give better body. The black color made by some of the Innuit tribes is made with blood and charcoal intimately mixed, which is afterwards applied to incisions in ivory, bone, and wood.
Among the Dakota, colors for dyeing porcupine quills were obtained chiefly from plants. The vegetable colors, being soluble, penetrate the substance of the quills more evenly and beautifully than the mineral colors of eastern manufacture.
The black color of some of the Pueblo pottery is obtained by a special burning with pulverized manure, into which the vessel is placed as it is cooling after the first baking. The coloring matter--soot produced by smoke--is absorbed into the pores of the vessel, and does not wear off as readily as when colors are applied to the surface by brushes.
In decorating skins or robes the Arikara Indians boil the tail of the beaver, thus obtaining a viscous fluid which is thin glue. The figures are first drawn in outline with a piece of beef-rib, or some other flat bone, the edge only being used after having been dipped into the liquor. The various pigments to be employed in the drawing are then mixed with some of the same liquid, in separate vessels, when the various colors are applied to the objects by means of a sharpened piece of wood or bone. The colored mixture adheres firmly to the original tracing in glue.