Spectrometric Analysis of Chinese Ceramics

Laser Ablation Spectrometry & X-Ray Fluorescence are used in the scientific analysis of Chinese ceramics

Spectrometric analysis of the elements (atoms) present in a material is based on a simple principle. This method has been around for at least half a century.
It is an analysis method based on the physics of different components (atoms) present in the material. This method uses the emitted electromagnetic waves of elements for analyzing the components of materials.

In principle when the chemical elements or atoms of a material are excited by induction of electromagnetic wave energy, either in the LA-ICP-MS process or X-rays in the XRF process, the atoms in the material re-emits the absorbed energy again in the form of electromagnetic waves. Each atomic element emits waves of a unique wave length, which allows the identification of each element in the material. 

The acquired composition of the material, the elements present in clay or glaze can be compared with data from kiln shards, obtained during excavations. This again allows to determine the kiln from which an item may have originated, because ancient kilns mined clay in their vicinity' thus each kiln clay had its own specific elemental combination. This can make it possible to identify the manufacturing  location. 

LA-ICP-MS
With the help of a laser a tiny amount of material is extracted from the test object, leaving a minute, virtually invisible small hole in the material. The material is then heated to thousands of degrees, whereupon it emits energy in the form of electromagnetic waves. These are then analyzed to determine the element it belongs to.

XRF (X-Ray Fluorescence)
With this method the atoms in the material are excited using X-rays. The material then re-emits energy in the form of electromagnetic waves (fluorescence), which is analyzed to determine the element.

Use of spectrometric analysis for authenticating antique ceramics

The tricky part is acquiring all the data for analyzing the relevant material components for the individual kilns. A huge amount of shards that are reliably connected to the respective kilns will be necessary, in order to get data of all the hundreds of kilns. But, the analysis should be doable even if only shards or items from a limited number of major kiln sites are analyzed. Only in this case items from kilns without data cannot be positively identified.

Once reliable data are available, however, spectrometric analysis should be fairly straight forward in clarifying whether an item was made at a supposed kiln.

Possible factors affecting the results:

• If the material composition of the clay or glaze did not differ much between different two or more kilns or periods, the material identity could only be limited to the concerned kilns as a whole.
• If clay composition did not vary muchr throughout the time of existence of a kiln, the time of manufacture may not be decided accurately.

However, due to the large number of mineral/chemical elements analyzed with this method, it is likely there will be some differences in most cases.

Note:
There are rumours that expert forgers are catching up on spectrometric analysis methods too and are now sometimes adding the necessary mineral elements to the clay to fool the instruments. Thus, we are not able to completely rely on this method alone either, in the future.

 

Go to Scientific Authentication of Ceramics