> Hyperspectral imaging in the visible and near-infrared ranges initially seemed promising. Unfortunately, the black redaction ink absorbed almost all light in the visible range, and in the NIR range, the two inks were rendered largely transparent. They were too similar to draw any conclusive results. Pottier and his collaborators got the best results with X-ray fluorescence (XRF) spectroscopy in a microscanning mode
Does anyone know what are the other use cases for these techniques? The article is very interesting! Thanks for sharing