Yulihong / Underglaze Red

Production Process

Copper-based pigment is painted onto the unfired body and sealed beneath a single transparent glaze, fired once at high temperature. Copper red is one of the most difficult pigments to control in the kiln: it requires a narrow reduction atmosphere to hold a stable red, and will shift to grey, brown, or vanish if firing conditions drift even slightly outside that range.

Historical Development

The technique appears in Yuan-dynasty production and recurs at technically ambitious moments across Chinese ceramic history — notably the Hongwu and Xuande reigns of the early Ming, and again as a deliberate revival during the Qing dynasty when kilns sought to demonstrate mastery of historically difficult techniques.

Distinguishing Characteristics

Because successful copper red is so firing-dependent, the clarity and evenness of the red is itself the primary indicator of technical success — many historical attempts survive with muted, uneven, or greyed colour, which is part of why a clean, stable red is notable rather than assumed.

Used together with cobalt blue on one object (青花釉里红), both pigments lie beneath the glaze and share one firing. Such pieces remain Underglaze Decoration.