MA-XRF and hyperspectral reflectance imaging for visualizing traces of antique polychromy on the Frieze of the Siphnian Treasury

Abstract

Of the once colourful decoration of antique Greek statues only few traces remain today. But these allow one to reconstruct part of the polychromy, based on visual and microscopic inspection and spot analysis with spectroscopic methods. For the first time we used mobile hyperspectral reflectance imaging in the visible and near infrared range and scanning macro XRF imaging for the investigation of remnants of antique polychromy on a stationary object. With this method of analysis we were able to reveal previously unknown traces of ancient paint on the Frieze of the Siphnian Treasury (around 525 BCE). This illustrates the capabilities of this techniques to obtain new insights in a well-described and investigated object. Further, we gained insight into the painting technique, involving an earth based preparation layer. Finally, we present an alternative way to the treatment of the hyperspectral reflectance data in order to obtain easily readable pigment distribution images in case of heterogeneous illumination.