Derwent Lightfast Colored Pencils 100 Tin Set of 100 4mm Wide Core 100% NEW. 100 colors Multicolor/100 Count Pack of 1. Derwent Lightfast pencils are formulated to be 100% lightfast meaning that the core is resistant to colour change and will not change for up to 100 years under museum conditions. All colours comply with internationally recognized lightfast testing standard ASTM D6901 as well as Blue Wool Scale ISO 105. Revolutionary oil-based core creates a buttery velvety texture allowing complete integration of. Your artwork will stand the test of time. Derwent Lightfast Coloured Pencils are 100% lightfast and will not fade for up to 100 years. International Buyers – Please Note.