1 - Color is a very misunderstood term for the beginning artist, as humans find it difficult to easily recognise the basic nature of color which is tone, hue, and chroma. Hue is the most obvious and refers to the wavelength of light visible. In other words whether it is red or green or blue. 2 - The word ‘hue’ is often found on cheaper tubes of paint. It indicates where the correct pigment has been replaced by another, or by a mixture to imitate the real thing. This is rarely a complete success, but it does save a lot of money for the manufacturer, and enables you to obtain a color for a lot less money than it would do otherwise.