Winsor & Newton Artisan Water Mixable Oil Colours - Permanent Sap Green - 37 ML is magnificently designed to look and work just like traditional oil paint. The key difference between Artisan and conventional oils is its ability to thin and clean up with water. Artisan has been specifically developed to appear and work just like conventional oil colour. The depth of colour, buttery consistency, light fastness, opacity/transparency, performance and drying times of Artisan, allow artists to use this range for all oil colour techniques. Sap Green Permanent is a rich mid-range green with a yellow undertone. Originally Sap Green was a lake pigment made from unripe Buckthorn berries.