Sanguine is an earth colour and contains red iron oxide which is mixed with Kaolin to obtain leads of an extremely rich colour. The different shades of sanguine are obtained by the addition of various oxides. They work well on their own or combined with black tinted paper. These pencils can also add emphasis to a coloured work. They are a traditional medium for life classes. A deep "rust" colour, sanguine is recommended for nudes as its colour resembles that of the skin when highlighted with white. When using a sharpened lead drawings can be accurate, the colour transparent and if drawn lightly the texture of the paper can show through. Lines are easily blended with the sanguine pencil and if a half-worn lead is used, the opacity increases in a direct relationship with the pressure exerted on the pencil.