means. Glazes like Nos. 1 and 2 will do quite well for elementary work but unless the appliances are to hand the manufactured article will have to be relied on for more finished and ambitious work.
If, indeed, you are already in possession of a good receipt for a fine colour and glaze, one quite worth while, so much the better. Mix it and feel the joy of the Compleat Potter unafraid of spoiling his own good shapes with a faulty or unknown glaze.
Admittedly, to get anywhere in an original direction systematic research is essential. One must keep on experimenting, keep on hoping, and keep on taking notes; but at the start let us not be too impatient or independent if we wish to produce good pots.
There is often among young potters a false pride that prevents them using, and among old potters acknowledging the use of, the manufactured article. Why this should be is a little difficult to understand. A painter might far more reasonably be ashamed to use modern tube colours or a stained-glass craftsman as logically insist on making his own glass, as a potter in the twentieth century refuse to avail himself of the wonderful range of glazes that modern research has placed at his disposal. These resources should be used intelligently, not mechanically, or by the book—artistically, inventively, secretly, if you will, but they should be used—until the multitudinous experiments have borne fruit and repeated trials
convince you that at last you possess some gem of research worth, as well it may be, the months of patient toil engendered in its production.
The various receipts are given on pages [183] and 184 without analysis of the composition of the paste or body to which they were applied. The first group have been used on common earthenware clays with complete satisfaction. They are to be considered as points of departure for future experiments in which they may be modified at will, and not regarded as a contribution to the science of glaze making.
In colouring it will be found that combinations of cobalt, iron, and copper oxides give an interesting range of simple blues or greens; iron and manganese browns; and so forth. The colour mass or stain is ground fine and lawned, and from about 2 to 7 per cent mixed with the colourless glaze mass, according to the depth of colour required. The ordinary under-glaze colours may be used to stain glazes, the percentage being fixed by small trials. For the rare colours—turquoise, crimson, or purple—a more complicated process is necessary and only perfected after many trials. The ingredients of these fine colours are naturally kept secret by their fortunate possessors.
It must be noted that a glaze suited to one body may peel or run off an unsuitable one. Then a colourant is affected differently by a lead or
an alkaline base in the glaze. Again, copper and iron oxides may help to flux a glaze, whilst cobalt or nickel will exert a contrary effect. Cobalt, being a strong colourant, will need a sparing use, whereas a similar percentage of iron will merely tinge the glaze mass. And so ad infinitum.
It is self-evident that any attempt to emulate the vast range of the modern ceramic chemist is doomed to failure. To a craftsman the fabrication of one fine individual glaze or lustre is an achievement of which he may be proud, and for which he will find abundant and varied uses. In this connection it is encouraging to the craftsman to learn from so high an authority as W. Burton, Esq., F.C.S., that it is impossible to obtain with purified oxides the fine tones got by the Orientals with impure materials. Further, that the simple glaze of the Persians—a mixture of clean white sand with soda or wood ash or potash—is still the best for under-glaze painting. Although tastes differ so widely, invariably it will be found that more and more heat will be the cry. Imperceptibly this leads to the desire for hard, cold, “fat” translucent glazes, neither matt nor glossy. And on the summit, far out of reach, stand the wonders of the Old Chinese.