Derwent Lightfast Colour Pencils have been formulated as 100% lightfast, this colored core combats the effects of UVA-radiation and maintains the longevity of colors on permanent display. Derwent Lightfast pencils are oil-based, smooth and creamy with a beautiful lay down of rich color. The thick core gives a dense colour application which brings vibrancy to any drawing. Artwork created will remain lightfast for up to 100 years under museum conditions. All colors comply with international lightfast testing standard, ASTM D6901.