Fig. 1
From: Visualising varnish removal for conservation of paintings by fluorescence lifetime imaging (FLIM)
Optical setup. Panel A presents the diagram of the optical setup. Panel B shows the top-view 3D rendering of the optical setup. The critical optical components were emphasised by making the the supportive components appear semi-transparent. Panel C is a photo of the assembled optical setup in use with the model painting. The components in the panels are numbered: 1 − laser, 2 − concave lens, 3 − variable iris aperture, 4 − convex lens, 5 − chromatic mirror, 6 − removable emission filter holder, 7 − emission filter, 8 − objective lens, 9 − objective lens holder, 10 − SPAD camera, 11 − wooden case with its lid removed, 12 − painting, and 13 − illuminated spot on the painting. The illuminated spot was larger (≈ 35 mm in diameter) than the field of view (13.5 × 18 mm2) captured by the camera