Derwent Lightfast pencils are oil based, smooth and creamy with a beautiful laydown of rich colour. They have been formulated as 100 percent lightfast, this unique coloured core combats the effects of UVA-radiation and maintains the longevity of colours on permanent display. The thick core gives a dense colour application which brings vibrancy to any drawing. Available in a range of 72 lightfast colours. The revolutionary core is resistant to prolonged colour change ensuring artwork will not fade for up to 100 years under museum conditions. Derwent Lightfast pencils are oil-based, smooth and creamy with a beautiful laydown of rich colour. What's more, they can even be used with a medium giving a painterly effect when dissolved.