X-ray Dark-Field Imaging for Improved Contrast in Historical Handwritten Literature

Abstract

If ancient documents are too fragile to be opened, X-ray imaging can be used to recover the content non-destructively. As an extension to conventional attenuation imaging, dark-field imaging provides access to microscopic structural object information, which can be especially advantageous for materials with weak attenuation contrast, such as certain metal-free inks in paper. With cotton paper and different self-made inks based on authentic recipes, we produced test samples for attenuation and dark-field imaging at a metal-jet X-ray source. The resulting images show letters written in metal-free ink that were recovered via grating-based dark-field imaging. Without the need for synchrotron-like beam quality, these results set the ground for a mobile dark-field imaging setup that could be brought to a library for document scanning, avoiding long transport routes for valuable historic documents.

Adapting an XCT-scanner to enable edge illumination X-ray phase contrast imaging

“…In summary, these contrasts allow to identify material properties and interfaces that would be difficult to spot with attenuation contrast alone. [4][5][6] Edge illumination phase contrast imaging (EI-XPCI) is a phase contrast technique particularly suited for industrial imaging. It can be performed with commonly available X-ray sources because of the relaxed requirements of the X-ray source [7].…”