Made of blue underglaze and enamelled ceramic , porcelain .
由蓝色釉下陶瓷和搪瓷，瓷器。
Engrave the veins of the underglaze red flowers with an engraving needle .
用刻针将釉里红花形刻出脉纹。
At jingdezhen pigment with a very low-grade cobalt content and high in iron impurities was applied to porcelains beneath the glaze and can be hard to distinguish from underglaze iron painting ( see cat . No. 1:23 ) .
