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.
OIL PAINTING ON TERRA-COTTA.
Upon terra-cotta of a light tint the design is drawn with a lead pencil; upon that of a dark tint, use the colored impression paper.
Place the article between piles of books, or fill a box with sand, and lay or stand it into this in the position required; see that the right arm rests upon an even plane with the article to be decorated.
A terra-cotta medium is made from a small quantity of gum arabic dissolved in water, to which is added a little syrup; go over the entire article with a flat brush dipped into the medium; when dry, repeat the wash. The article is now ready for the oil colors. Mix these with flake white, and use McGuilp instead of turpentine; lay the colors on fairly thick, and let them dry for some hours, then tint and finish with the colors necessary, without the flake white, but still using McGuilp. When finished and quite dry, varnish with best copal or mastic.
The artist should have at hand two or three fine oil brushes, a flat brush, and the necessary colors. Those being indispensable are the following: black, burnt light ochre, terra di sienna, Indian red, and flake white.
The artist is reminded that vases of antique shape look best when decorated in antique designs.