Fig. 14

a Close-up picture of case study LM-8368. The green and blue triangle and the magenta border indicates where the references were taken for the three acquisitions. The blue and green rectangular areas delimits the area where the associated reference performs well. b–e Spectra comparison for amber and red colored glass from three acquisitions performed using three different transparent areas as reference. The bands’ position of the Cu nanoparticles (np) and the Fe³⁺-S complex are indicated with arrows. Regarding Fe²⁺, it was preferred to indicate the band width for this chromophore, since the maximum of its band falls outside the camera spectral range (1100 nm), and the red-NIR region is distorted by noise and artifacts from the radiometric correction