Here, I'll quickly explain some important terms from the topic of colours:

 

Hue


The hue is determined by the wave length of a colour, which makes it possible to distinguish between different colours. 

Saturation


A colour's saturation is a measure of its colourfulness. The level of saturation tells, how much of a spectrum colour is present in a colour. 

Lightness


Lightness is a means of specifiying a colour's physical luminous intensity (candlepower). The measurement unit for this luminous intensity (or light intensity) ...