Beneath the Glaze and Above It

7 days ago

3 min read

The phrase “underglaze blue and overglaze enamels” appears in descriptions of Japanese porcelain. It is easy to read past it on the way to the artist’s name or date. Yet those few words tell us something about how the decoration was built.

The colours belong to different stages of firing. Knowing their sequence gives us a more precise way to look at a painted surface.

Colour beneath the glaze

In underglaze painting, the decoration is applied before a transparent glaze covers it. The vessel is then fired. Cobalt is used to produce the blue familiar from blue-and-white porcelain. The Museum of Oriental Ceramics, Osaka, also describes underglaze decoration made with iron and copper pigments. Underglaze is a position in the making process, rather than the name of one colour. [1]

On a blue-and-white piece, follow one painted line. Does it stay narrow, widen into a wash, or gather into a darker area? These are useful observations to record before trying to identify a kiln or maker. A description such as “a pale blue wash inside a darker outline” gives another person something specific to find in the photograph.

Colour added after firing

Overglaze enamels are applied to a surface that has already been glazed and fired. A further firing, at a lower temperature, fixes this decoration. The Japanese term iro-e is commonly used for this coloured enamel decoration. It can appear alongside underglaze painting on the same vessel. [1]

Blue needs particular care. Gallery Japan’s explanation of traditional overglaze enamelling includes blue among the available colours. A blue passage therefore cannot be assigned to the underglaze stage on colour alone. The object’s documented technique matters. [2]

A dish that stopped between stages

An unusually helpful example belongs to the Smithsonian’s National Museum of Asian Art. Its Dish with unfinished enamel decoration is catalogued as Arita ware, Kakiemon type, from 1670–1700.

The museum explains that the blue portions were painted in cobalt beneath a clear glaze. Other parts of the design were left ready for enamels, which were never added. The reason is unknown. [3]

This unfinished dish makes the sequence easier to imagine. Look at the museum’s photograph and follow the blue decoration, then examine the areas identified in its description as awaiting enamel. The gaps let us consider what another firing would have added. They also remind us to distinguish a museum’s documented explanation from a story we might invent for an object.

Two techniques within one design

For a completed example, the Metropolitan Museum of Art records its early eighteenth-century Dish with Design of Spools of Thread as porcelain combining underglaze blue and overglaze enamels. It identifies the work as Hizen ware, Nabeshima type. [4]

Use the collection image to study how the coloured areas relate. Which parts carry outlines? Where does colour fill a shape? How much white porcelain remains visible? The technical description gives a starting point, while these questions direct attention to the painter’s arrangement.

When looking at another piece online, ask for a clear view of the whole decorated surface and close photographs of the areas you want to understand. Read those images alongside the catalogue description and condition report. A photograph can help you notice a boundary or a change in gloss; it cannot, by itself, establish the full firing history or an attribution.

The next time a label names both underglaze and overglaze decoration, return to the surface. Try to follow the order in which its colours arrived.