Relationship Between Celadon, Qingbai, and White Wares

Iron oxide plays a fundamental role as the primary colorant in ancient Chinese ceramic glazes. The earliest glazed ceramics in China, often referred to as proto-porcelain or green ware, owe their coloration to the presence of iron oxide. This discovery was likely accidental, as iron oxide naturally exists in the raw materials—such as rocks, clay, and plant ash—used by early Chinese potters. The final glaze color is influenced by several factors:

1) Iron Oxide Content

• 0.5-2%: Ivory to straw tones
• 2-3%: Yellow tones
• 3-4%: Amber tones
• 4-5%: Amber-brown tones
• 6-8%: Varying degrees of black

2) Firing Atmosphere

• Oxidation: Converts iron oxide to ferric oxide (red iron oxide), leading to warmer tones.
• Reduction: Converts iron oxide to ferrous oxide (black iron oxide), resulting in cooler tones.
  • Ferrous oxide (0.5-1%): Produces icy-blue tones, characteristic of Qingbai wares.
  • Ferrous oxide (4-8%): Produces glossy black tones.

3) Presence of Titania (TiO2)

When titania (0.2-0.5%) is present in the glaze during reduction firing, a wide range of green hues, from grey-green to olive-green, can emerge. This is typical of celadon wares, with famous examples including Yue, Longquan, and Yaozhou wares.

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Historical and Technical Context of Celadon and Qingbai Wares

Celadon wares have been produced in China since the Shang Dynasty, displaying a wide range of color tones due to variations in glaze composition and firing techniques. Occasionally, celadon can exhibit a light bluish tone, especially during the early Southern Song period when lime glazes were thinly applied, resulting in a more transparent and bluish appearance.

 

Qingbai wares, typically produced in kilns like Hutian, are characterized by their icy bluish tone, thin potting, and white translucent body. Celadon, by contrast, usually features a thicker body with a more greyish paste. This sometimes creates ambiguity when distinguishing between certain celadon and Qingbai wares, especially those from Fujian that imitate Longquan celadon or Hutian Qingbai wares.

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Classification Challenges

The distinctions between celadon and Qingbai wares are not always clear-cut. Some Fujian celadon wares, despite having a Qingbai-like color tone, are classified as celadon due to other characteristics such as thicker potting and greyish paste. This raises questions:

• Did potters intend to produce a greenish celadon glaze but ended up with a Qingbai tone due to firing inconsistencies?
• Or was a Qingbai tone their deliberate goal?

These questions remain unanswered due to insufficient archaeological evidence. The subjective nature of classification often depends on the criteria used—whether color tone, glaze composition, or potting style. Ultimately, neither classification is inherently right or wrong.

 

The above photo displays a group of celadon and qingbai ceramics. The group enclosed in green represents typical celadon, characterized by a thicker lime-alkaline glaze. The group enclosed in white consists of typical Qingbai ceramics. The group within the yellow line is Fujian celadon, some of which exhibit a Qingbai color tone (highlighted with a red line). From a color tone perspective, these pieces appear to be Qingbai. However, they are classified as Fujian celadon. Why is that? The argument lies in their physical characteristics: they are more thickly potted, have a grayer paste, and share similarities with more typical celadon in terms of glaze tone. Therefore, classification considers not just color tone but also other distinguishing features commonly associated with this type of bowl. To a certain extent, this classification involves some subjectivity. Objectively, certain questions remain unanswered. Did the potters intend to produce a more greenish celadon glaze, but due to uncontrollable firing conditions or glaze content issues, a Qingbai-like tone emerged instead? Or was the potter's intention to achieve a Qingbai tone from the beginning? Unfortunately, archaeological excavations have not provided enough information to answer these questions definitively.

 

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White Ware Classification Issues

A similar classification challenge arises with white wares. True white ware is transparent due to the absence of iron oxide. However, many white wares exhibit a light bluish tone where the glaze pools, likely due to small amounts of iron oxide. Whether to classify these as Qingbai or white wares often depends on subjective interpretation.

 

This group of Southern Song Dehua ewers has colour that range from light bluish to white.

   

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Scientific Perspective on Chinese Ceramics

For those interested in understanding ancient Chinese ceramics from a scientific perspective, the following references are invaluable:

• Chinese Glazes by Nigel Wood, particularly the chapter on "Iron in Glazes."
• 中国古陶瓷的科学 by Professor 张福康 (for readers proficient in Chinese).

Understanding the history, production processes, and scientific explanations for glaze colors offers a more meaningful perspective than rigidly adhering to classification terminology.

By: NK Koh (29 Aug 2009)
Updated: 27 Nov 2010, edited with ChatGPT on 8 Feb 2025.