Enamels, like Celadons, may be of any colour. They are always burnt in so as to amalgamate with the cover glaze, even if that cover glaze be itself coloured and therefore Celadon. Also there are but a few colours which can be applied before glazing, that is, upon the paste or body directly. We have seen that blue and red were so applied. This brings us to the other development. The Keen-lung class of blue and red under the glaze was derived from that discovered in the Yung-ching period. Its application was developed with surprising skill by the finest workmen, so that the application of copper red under the glaze, in combination with blue, gave splendid opportunities for these artists to display their pre-eminent skill for freehand drawing in applying designs upon the biscuit porcelain before the glazing took place. If, for example, you pass your hand over a piece decorated under the glaze, you will find a surface perfectly smooth, the colour has sunk into the paste.
The next note is worth remembering, because it may be applied as a practical test to distinguish between the old and the modern blue under the glaze. This test of modern blue is to be found with the finest strokes, whereas in the old work each stroke is perfectly smooth or uniform in its outline, never laboured, never hatched, but simple strokes which plainly follow the American plan of never taking three strokes when one stroke will do. Most of the modern work reveals a tiny blue dot at the pull-off of the fine hair brush or pencil. The drawing and writing of the Chinese was always done by means of a pencil held perfectly upright by the fingers, so that by examination of the pencil marks it is quite easy to see whether the blue lines have inequality, especially at the point where the brush is removed, and our readers may detect forgeries of the old marks as well as the old drawings by noticing this blue dot at the end of the stroke. It is never found upon an old piece.
The coral red family, which belongs peculiarly to this period, is extremely pleasing, and a very fine result is secured when used with blue under the glaze, leaving the design outlined in red, so that the red, white, and blue harmonise perfectly. But the coral red was also used under the glaze as a ground colour. Then it was thickly powdered with white chrysanthemum leaves and flowers, and it had white reserves often decorated with sprays of conventional white lotus, chrysanthemums, and magnolia. The Chinese varied the colours in their decoration with wonderful effect. Blue under the glaze was, as we have seen, associated with reds under the glaze, but it was quite effective with enamels over the glaze, and we may take this as the next class of the period. The design, or any part of it, was applied to the paste, then the piece was glazed and fired so that on coming from the kiln it was simply a white porcelain piece having blue, or red and blue, decoration under the glaze. Then enamel colours were used to complete the design, such as green enamels with the blue designs showing through them and thin dull reds under the glaze, as before noted, whilst the rest of the piece was coated with decoration in yellow, blue, or even white enamel colours.