Reverse Engineering Lusterware Porcelain
Graduate Student: Celia Chari
Undergraduate Student: Zane Taylor
Meissen porcelain was Europe’s first successful replication of Chinese porcelain with decorative over-glaze enamels, invented by Johann Böttger in the early 18th century [1]. A full pallet of colors was desired to replicate Chinese ceramics during the Böttger period of the Meissen factory’s production. While this goal was not realized for years to come [2], rare “mother of pearl” and lustrous purple glazes were produced by applying gold nanoparticles to the top glaze [1], [3].
Most historical artifacts such as Böttger lusterware exist within public trusts and museums that are actively involved in their documentation and restoration. Investigative scientific methods are increasingly being applied to analyze the characteristics of historical artifacts, detect counterfeits, and contribute to historical knowledge. All of these are applicable to Böttger lusterware, the production of which was highly secretive and about which little is known to this day [1]. Expanding our investigations to Böttger lusterware with tools typically reserved for metals and stoneware will reveal more of the nature of this lusterware for the historical community [3].
Limited historical records suggest that the Meissen factory came to use aurum fulminans, gold (I) hydrazide, in the synthesis of the luster. This compound decomposes into gold ions that diffuse into the porcelain’s outer glaze and are reduced by the atmosphere into their metallic, nanoparticle state. This forms a gold nanoparticle layer on the surface of the lead-rich glaze that creates the signature Böttger luster [1]. It is important that we distinguish this color from Purple of Cassius, a non-lustrous historical alternative that arises from gold nanoparticles suspended in tin oxide instead of lead oxide [2]. In contrast to Purple of Cassius, tin is not present in Böttger lusterware.
In this project, we have reverse-engineered and characterized Böttger lusterware as consisting of a body of kaolinic clay, feldspar, and silica with needle-like mullite inclusions [4], [5]. Atop this body are annealed clear and base glazes for decorations, over which the lustrous, gold nanoparticles are placed using the reduction of gold (III) chloride. Our studies attempt to understand the materials and manufacturing conditions required to produce lusterware in the original Meissen factory, providing scientific insight and information needed to authenticate Böttger lusterware. Different manufacturing methods can affect the chemistry, nanoparticle size and nanoparticle spacing within the top glaze, ultimately affecting the hue and luster of the glaze. Using models that probe the nanoparticle layer, we are investigating the theoretical origin of said luster by studying plasmonic and scattering effects that manipulate the optical properties of the top glaze [6], [7].
[1] N. Zumbulyadis, “‘...with a dreadful bange’ - A Chemical History of Bottger Lustre,” Keramos, vol. 2013, no. 222, pp. 1–16, 2013. [2] N. Zumbulyadis, “DECORATING WITH EXPLOSIVES: THE USE OF AURUM FULMINANS AS A PURPLE PIGMENT,” Bull Hist Chem, vol. 39, no. 1, p. 11, 2014. [3] A. Asman, “Reverse Engineering of 18th Century Meissen Porcelain,” Northwestern University, B.S. Thesis in Materials Science and Engineering, Jul. 2009. Accessed: Feb. 13, 2020. [Online]. [4] Z. Chen, “Ceramic Bodies of 18th Century Meissen Porcelain,” Northwestern University, Ceramic Body Studies., Jul. 2009. Accessed: Feb. 13, 2020. [Online]. [5] X. Chen, “Authentic Lusters of 18th Century Meissen Porcelain,” Northwestern University, STEM Studies, Jul. 2009. Accessed: Feb. 13, 2020. [Online]. [6] N. Khlebtsov and L. Dykman, “Plasmonic Nanoparticles: Fabrication, Optical Properties, and Biomedical Applications,” in Handbook of Photonics for Biomedical Science, vol. 20102371, V. Tuchin, Ed. CRC Press, 2010, pp. 37–85. [7] I. Grguraš et al., “Ultrafast X-ray pulse characterization at free-electron lasers,” Nat. Photonics, vol. 6, no. 12, pp. 852–857, Dec. 2012, doi: 10.1038/nphoton.2012.276.
a) Example piece of Meissen porcelain (Art Institute of Chicago 1991.1a.), b) close-up of teapot showing Böttger luster, c) reverse-engineered replicas of Böttger luster viewed at different angles, d) STEM images showing gold nanoparticles sitting in the top glaze of authentic Böttger lusterware.