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Figure 1-20. Visible induced luminescence images of a detail from a wall painting fragment from the British Museum (Winged youth from the Tomb of the Nasonii, 1883,0505.5) acguired (a) with a mixture of radiation from LEDS (R, G and B) and tungsten lamps, and (b) with radiation from LEDS only. Ambient stray radiation can arise from non-ideal working conditions such as a room where it is not possible to exclude external radiation or in which there are luminescent objects. Whilst some of these concerns can be addressed under controlled conditions or with nocturnal image capture, it is often not possible to completely exclude ambient stray radiation in a museum or gallery environment. Figure 1-21. UV-induced luminescence images image of a detail from a wall painting fragment from the British Museum (Winged youth from the Tomb of the Nasonii, 1883,0505.5) (a) with ambient stray radiation and (b) in the absence of ambient stray radiation. The images are as shot. Version No. 1.0 25 Date : 14/10/2013
