Winsor & Newton Cotman Water Colours are a range of water colours that are made to our normal high quality standards but costs are kept to an economical level by replacing some of the more costly pigments with less expensive alternatives. Each colour has good transparency, excellent tinting strength and good working properties. Yellow Ochre is a warm yellow. Originally made from natural iron oxides found in earth, it is one of the oldest pigments used by mankind. A synthetic version became available in the 1920s.