To obtain the best colour from the copper oxide in this glaze it was necessary to regulate the firing to a nicety, the margin between success and failure being exceedingly small. Naturally, too, the results varied widely in quality and tone; but the permanent characteristics of the K’ang Hsi sang de bœuf are (1) a brilliant red varying in depth and sometimes entirely lost in places,[268] but always red and without any of the grey or grey blue streaks which emerge on the flambé red and the modern imitations of the sang de bœuf; (2) the faint crackle of the glaze; (3) the stopping of the glaze at the foot rim. The colour of the glaze under the base and in the interior of vases varied from green or buff crackle to plain white. The secret of this glaze, which Père d’Entrecolles tells us was carefully guarded, seems to have been lost altogether about the end of the K’ang Hsi period. Later attempts to obtain the same effects, though often successful in producing large areas of brilliant red, are usually more or less streaked with alien tints such as grey or bluish grey, and are almost invariably marred by the inability of the later potters to control the flow of the glaze which overruns the foot rim and consequently has to be ground off. But it is highly probable that the modern potter will yet surmount these difficulties, and I have actually seen a large bowl of modern make in which the ox-blood red was successfully achieved on the exterior (the interior was relatively poor), and the flow of the glaze had been stopped along the foot rim except in one or two small places where the grinding was cleverly masked. So that it behoves the collector to be on his guard.
Fig. 2 of Plate [88] shows another type of red, also classed as lang yao, which has the same peculiarities of texture as the sang de bœuf, but the colour is more of a crushed-strawberry tint, and has in a more marked degree that thickly stippled appearance which suggests that the colour mixture has been blown on to the ware through gauze. This is probably the ch’ui hung or soufflé red mentioned by Père d’Entrecolles in connection with the yu li hung. The same glaze is often found on bowls, the colour varying much in depth and the base being usually covered with a crackled green glaze beneath. This crackled green is a very distinctive glaze, highly translucent and full of bubbles, like the red lang yao, and it is sometimes found covering the entire surface of a vase or bowl and serving as a background for paintings in famille verte enamels. It seems, in fact, to be the true green lang yao, and one is tempted to ask if it was not in reality intended to be a sang de bœuf red glaze from which a lack of oxygen or some other accident of the kiln has dispelled all the red, leaving a green which is one of the many hues produced by copper oxide under suitable conditions. These conditions might well be present in such an enclosed space as the foot of a bowl; and if they happened to affect the whole of the piece, what more natural than to trick out the failure with a gay adornment of enamel colours?
On the other hand, what is commonly known as green lang yao is the brilliant emerald or apple green crackle which has already been discussed on p. [102]. But why this colour should be connected in any way with the Lang or any particular family is a mystery. The method of producing it is transparently obvious—a green enamel laid over a stone-coloured crackle; and there are examples of all periods from the Ming down to modern times. Indeed, the modern specimens are only distinguished with the greatest difficulty from the old.
To return to the history of the period from which we digressed to discuss the lang yao, the progress of the reviving industry suffered a rude set-back between 1674–1678 when the Imperial factory was destroyed during the rebellion of Wu San-kuei, viceroy of Yunnan. It is improbable that up to this time any notable development had taken place in the manufacture of porcelain, and those who think to flatter a specimen by suggesting that it is “very early K’ang Hsi” are likely to be paying a doubtful compliment. When, however, peace was restored and the factory rebuilt, a veritable renaissance of the porcelain industry began. In 1680[269] an official of the Imperial household was sent to reside at the factory and to superintend the work; and we are told in the T’ao shuo[270] that “previously to this the first-class workmen had been levied from the different districts of Jao Chou; but now all this forced labour was stopped, and as each manufactory was started the artisans were collected and materials provided, the expenses being defrayed from the Imperial exchequer and the money paid when due, in accordance with the market prices. Even the expenses for carriage were not required from the different districts. None of the proper duties of the local officers were interfered with; both the officials and the common people enjoyed the benefit, and the processes of manufacture were all much improved.”
The success of this new movement was assured by the appointment in 1682 of Ts’ang Ying-hsüan
to the control of the Imperial works. We are not told how long this distinguished person retained the directorship, but his merits are clearly indicated in the encomiums of a subsequent director, the celebrated T’ang Ying. In his “History of the God of the Furnace Blast,” the latter states that when Ts’ang was in charge of the factory the god laid his finger on the designs and protected the porcelain in the kiln, so that it naturally came out perfect. Unfortunately, the notice of Ts’ang’s work in the T’ao lu[271] is in the conventional style, and extremely meagre. The earth used, we are told, was unctuous, the material lustrous and thin. Every kind of colour was made, but the snake-skin green (shê p’i lü), the eel yellow (shan yü huang), the (?) turquoise (
chi ts’ui), and the “spotted yellow” (