Winsor amp newton cotman water colour 21ml tubes winsor newton 0308179 this cobalt blue hue 179 water colour 21ml tube has been made to winsor amp newtons high standards yet remains economical thanks to the more costly pigments being replaced by less expensive alternatives producing good tinting strength and transparency many of the pigments used in this colour remain organic while artists have the choice of intermixing the cotman water colour with the artists water colour range de