ABSTRACT

Egyptian faience is a non-clay ceramic semi-transparent material formed of a quartz core and alkali-lime glaze. Previous investigations have identified production techniques by using microstructure images obtained from invasive methods. Optical coherence tomography (OCT) is a non-invasive 3D imaging technique that produces virtual cross-sections of transparent and semi-transparent materials. A previous study by one of the authors demonstrated the feasibility of non-invasive investigation of microstructures of Egyptian faience using 930 nm OCT, but the limited probing depth prevented viewing down to the quartz core of the objects. This paper shows that an in-house developed OCT system using a longer wavelength (2 µm) was able to image the full microstructure from the top glaze layer down to the core, allowing rapid and non-invasive studies of intact objects and demonstrating the potential for surveying large museum collections. OCT virtual cross-section images at 5 wavelengths, 550, 810, 930, 1300 and 1960nm, were compared and the optimum wavelength for OCT investigation of Egyptian faience microstructure was found to be 2 μm.

摘要

埃及彩陶是一种非粘土陶瓷半透明材料，由石英芯和碱石灰釉组成。以前的研究已经通过使用从侵入性方法获得的微结构图像来确定生产技术。光学相干断层扫描 (OCT) 是一种非侵入性 3D 成像技术，可产生透明和半透明材料的虚拟横截面。其中一位作者之前的一项研究证明了使用 930 nm OCT 对埃及彩陶微结构进行非侵入性研究的可行性，但探测深度有限，无法观察到物体的石英核心。本文表明，内部开发的使用更长波长（2 µm）的 OCT 系统能够对从顶部釉层到核心的完整微观结构进行成像，允许对完整物体进行快速和非侵入性研究，并展示调查大型博物馆藏品的潜力。比较了5个波长550、810、930、1300和1960nm的OCT虚拟截面图像，发现OCT研究埃及彩陶微结构的最佳波长为2μm。