First outline with a lead pencil the subject to be painted; if tracing is preferred, use tracing paper, and transfer the design upon the article, by means of a colored transfer paper. The terra-cotta is now immersed in water; when thoroughly saturated, take it out, and with a soft sponge absorb all the superfluous moisture. If, during the process of painting, some of the parts become too dry, moisten them with a flat brush dipped into water.
Have on hand a sufficient quantity of white enamel powder, ;and with a glass muller grind this upon a ground glass slab until perfectly smooth, with water, adding a little gum water (dissolved gum arabic), until it assumes the consistency of cream. Apply this to the surface to be painted, going over it a second time, so :as to cover the tint of the ware. The enamel should be put on heavy enough so that it appears raised from the flat surface, being careful to spread it on very evenly, that none of the parts are coated lighter than others of the design. Enamel will stand firing several times, and such parts not brought out sufficiently can be restored by retouching the same, and subjecting the article to a second firing.
If the design is to be in natural colors, these are painted over the enamel after having been fired, proceeding in the same manner as in china painting. Some colors will bear mixing with the enamel before firing; in such case the dry enamel colors (China) are used, thoroughly mixed with the white enamel. Steel grey, neutral grey, blues and yellows are among the colors that bear mixing. The first three are best adapted for mottled or clouded backgrounds, if such are desired. The glaze contained in the colors and enamel when vitrified by firing, produce the effect of Limoges ware.
For ornamental work the relief enamel colors can be used successfully in the way of bead work, as well as in the entire design, they being already mixed in a powder state, consisting of about twenty-four different tints.
In doing larger pieces, where a quantity of color is used, the former instructions are to be preferred. If vases are decorated, intended for use, the inside should be washed with a mixture of enamel and color to give it a glaze, and thus prevent the outer decoration from being injured by the penetration of liquids.
Before taking the article to be fired, place it where it will become thoroughly dry, as it cannot be fired in a moist state. The Barbotine ware, which has lately come into the market, can be effectively decorated in the above manner.