Waterfall plot and surface plot (b) for the flash extinction from one xenon arc lamp, with one spectrum every 221 μs; the grey curve in (a) displays the ASTMG173 1000 W/m2 reference spectrum; the black arrow indicates the direction of extinction, i.e. from red to blue curves; (c) time series for selected wavelengths from data in (a) and (b), normalized over each curve’s maximum.