**4. Comparison with Painted Enameled Metalware**

The characteristics of porcelain and metal enameling were expected to be very much linked to each other in terms of the pigments/opacifiers used and the firing conditions employed. At the end of the 17th and early 18th century in China, enameling workshops both in charge of metal and porcelain enameling were established in the Forbidden City by the Jesuit mission to satisfy the demand of the Kangxi Emperor [4–8]. These workshops are considered to have been in close contact with each other [27]. The present study has shown that the material characteristics and production technology of 18th-century Chinese painted enameled porcelains and the painted enameled metalware of the same period are very similar. Pigments/opacifiers of European origin, such as Naples yellow lead pyrochlore pigment (yellow to green enamels), colloidal gold (red, orange and pink enamels) and lead arsenate phases (white and blue enamels) as well as similar lead-based glass compositions were identified in both of the enameled ware types. However, with the present state of knowledge, some differences can be noted on the diffusion of these new technologies in China. Tables 5 and 6 chronologically compare the appearance of European technologies for blue, white, yellow/green and red/pink enamels of porcelain and metalware, respectively.


**Table 5.** Chronological summary of the innovative technologies evidenced in Chinese enameled porcelains (A: arsenic-based apatite).


**Table 5.** *Cont.*


P.w.: palace workshop; J.I.F.: Jingdezhen Imperial Factory; J.p.k.: Jingdezhen private kiln; As-blue: European cobalt; Sb-N.y.: Sb-rich Naples yellow; Sn-N.y.: Sn-rich Naples yellow; s: small intensity; *ancient Ming technology: Asian blue; hematite red;* MGxxxx: Musée national des arts asiatiques—Guimet

inventory number.

**Table 6.** Chronological summary of the innovative technologies evidenced in Chinese enameled metalware [14].


Regarding the blue overglaze enamels studied so far, the change from Ming blue (made with Asian cobalt ores) to As-rich blue (pure European cobalt ores or mixing with Asian ones) is suggested

**Table 5.** *Cont.*

for the artifacts assigned to the end of the Kangxi reign on the basis of the decor style. It seems that both types of blue were used in the MG5250 "Imperial" bowl [12]. This bowl also exhibited the Raman spectrum characteristic of the use of colloidal-gold-based (*Famille rose*) enamel. Naples yellow pyrochlore, tin-rich, was the first European technology imported, but the addition of antimony was expected in the MG5696 "Imperial" bowl [12]. A weak signal of cassiterite was even detected in a similar shard [17]. It can be also noted that the MG5250 bowl is assigned to have been made at the palace workshop; the same innovative technology of enameling was observed for the MG3361 pencil water dropper assigned to have been made at the Jingdezhen Imperial Factory [12]. This indicates a very rapid transfer of technology from the palace workshop managed under the Jesuits' guidance to the imperial kilns at Jingdezhen. The Sn-rich Naples yellow (in yellow and green enamels) appears to have been used more frequently than the Sb-rich homologue up to the mid-18th century. The addition of Naples yellow increased the lead content. The use of cassiterite seems be exceptional, and its use must be confirmed by an examination of shard sections of similar artifacts.

It is worth mentioning that cassiterite was identified in the painted enamels of the metalware, as an opacifier, for a Kangxi *cloisonné* metalware piece and the exceptional painted and *cloisonné* Qianlong ewers from the French emperor's collection. Regarding enameled porcelain, Sn- and Sb-rich Naples yellow pyrochlores appear to have been used since the final period of the Kangxi reign. The same conclusions can be drawn for the use of colloidal gold for red to pink colors. By comparison, it appears that almost all enameled metalware was prepared with the European technologies, including As-rich cobalt, although enamel traditional recipes such as Ming blue were used simultaneously with new ones (Ming blue was used for underglaze decor). More artifacts must be analyzed to confirm this point.
