2025-05-19 Chinese Traditional Color Collection and Detection Research IV

The "Eastern Traditional Color Plan" initiated by the Guizhou Moutai Group, jointly undertaken by the Color Institute of the Research Center for Art and Science at Tsinghua University and the Color Design and Application Laboratory of Tsinghua Qingdao Art and Science Innovation Institute, has recently successfully completed its phased task. This phase focused on the physical sampling and color data analysis of porcelain pieces from the Northern Song Royal Kiln. The next step of the project will continue to advance the collection of other traditional material color samples.

Ru Yao is one of the five famous kilns in the Song Dynasty, known as "Ru, Guan, Ge, Jun, Ding," among which the Northern Song Royal Ru Yao is the most precious. Its glaze color is elegant and smooth, rich in layers, and has been known as the "crown of celadon" since ancient times. As the Song people said, "The汝River runs for hundreds of miles, with landscapes on both sides, and kilns blazing everywhere," vividly depicting the thriving scene of Ru Yao firing in the Ru Zhou area at that time.

To scientifically record the colors rich in Eastern aesthetic connotations, known to the ancients as "sky blue," "powder blue," "moon white," "shrimp blue," and "clear red," the project team strives to restore their true color appearance and reveal their visual characteristics in historical context through actual sample color collection and data analysis.

The samples collected this time include porcelain pieces unearthed from the sites of Ru Yao, Lin Ru Yao, and other kilns, covering eight representative traditional color names: sky blue, powder blue, shrimp blue, azure, moon white, bean green, green onion, and clear red.

The glaze color is not only influenced by the formula but also closely related to the firing atmosphere, temperature, and microstructure of the glaze layer. Taking the sky blue glaze as an example, studies have shown that its soft blue-green hue is not caused by a single pigment, but by the combined action of micron-sized calcium longstone crystals and submicron-sized phase structures: iron ions selectively absorb at high temperatures, while nanostructures scatter light coherently, forming a unique "structural color."

Structural color (structural color) is also known as physical color. Unlike pigmentary color (pigmentary color, also known as chemical color), which is the color shown by certain compounds that absorb specific wavelengths and does not change with the observation angle, structural color is achieved by changing the microscopic interface structure to cause light to reflect, refract, and interfere at the interface, resulting in different luster and color effects from different angles.

We use high-precision spectrophotometers and standard lighting systems (D65 light source, illuminance controlled at 500±50 lux, specific observation angles) to measure the Lab, LCH, RGB, and other data of the glaze surface point by point, while avoiding patterns, cracks, highlights, and shadows on the porcelain pieces. The porcelain surface is uneven, and the glaze is smooth, making it highly susceptible to environmental interference during color measurement. Therefore, the entire experiment maintains a uniform three-dimensional light field to ensure the authenticity and reliability of the data.

The porcelain pieces collected this time come from multiple kiln sites such as Wenmiao, Zhanggong Lane, Dayu, and are important historical witnesses of the imperial porcelain used in the Northern Song Dynasty. We hope to record the "fingerprints" of these colors through high-precision digital coloring methods and provide basic data support for future cultural relic restoration, cultural and creative development, and color education.

Color is not only a language of beauty but also a signal of civilization. The light hidden beneath the porcelain glaze is the ancient wisdom that we reignite today.