Multispectral images of ostraca: acquisition and analysis

We examine how multispectral imaging can be used to document and improve reading of ancient inscriptions. The research focuses on ostraca, texts written in ink on ceramic potsherds. Three corpora of Hebrew ostraca dating to the Iron Age II were imaged in visible and near infrared light using a state-of-the-art commercial spectral imager. To assess the quality of images, we used a new quality evaluation measure which takes into account various contrast and brightness transformations. We show that there exists a wavelength range where the readability of ostraca is enhanced. Moreover, we show that it is sufficient to use certain bandpass filters to achieve the most favorable image. Our study paves the way towards a low cost multispectral method of imaging ostraca inscriptions.

► Multispectral imaging can improve the readability of ostraca inscriptions.
► A new method for finding the optimal wavelength to image an ostracon is presented.
► Spectral images of 33 Hebrew ostraca from the Iron Age were taken and analyzed.
► A low cost multispectral imaging system designed for ostraca, is suggested.