Fig. 1From: The lightfastness of early synthetic organic dyesa Summary of lightfastness results from Thorpe et al. for textiles dyed with synthetic and natural dyes in the late nineteenth century; b approximate fading of the ISO Blue Wool standards as a function of illuminance (daylight through glass) and irradiance hours. Vertical lines indicate possible scenarios for the standard fading period used by Thorpe et al.Back to article page