Fig. 7

a Visible light detail of face and clothing. René Gerritsen Art & Research Photography; b false-colour UV-induced fluorescence image (RGB: 725, 650, and 575 nm); c False-colour spectral unmixing map displaying the distribution of fluorescence endmember spectra shown in e, including the ‘red’ endmember with 620 nm emission peak, the ‘blue’ endmember with 707 nm emission peak, and the ‘green’ endmember with a slowly decreasing emission intensity; d raw fluorescence emission spectra from the FIS data cube from which the endmember spectra (e) were calculated to make the map in c; e Endmembers used for spectral unmixing. The ‘red’ and ‘blue endmembers were calculated by subtracting off a scaled spectrum of the component with slowly decreasing emission, shown with a ‘green’ dashed line