Colour is often called a property of light (Newton went to a great deal of trouble to shine  a light through a glass prism and show the spectrum of colours (Red, Orange, Yellow, Green, Blue, Indigo, Violet -  As kids we used the mnemonic ‘Roy’s golf bag is violet’ to remember the order of hues. ) Like many things we experience, colour is more a creation or property of our brain actually which interprets it via the rods and cones (specialised cells of the retina in the eye). Humans have 3 types of cones , sensitive to different wavelengths of colour. The rods are most sensitive to light and dark changes. More information if you’d like on this link    -     http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html

Our experience of colours is not just dependent on the wavelength of the light rays that hit our retina, but also the visual context in which our brain perceives it- things such as background colours, lighting and even cultural influences. You will do some fun exercises later and see some interesting phenomena for yourself. (don’t worry, the science insights provided here are the minimal necessary to put pigments into perspective, The real goal of our colour model is to allow you to mix what you are wanting to mix and harmonise knowledgeably.

It is important to understand that Hue, Chroma ( related to Saturation) and Brightness (related to value and hue) are all attributes of colour. The word colour (or colour) is commonly used when referencing all or any of these attributes, however, to be specific, you need to learn to use all three terms distinctly and descriptively.\

Regardless of the medium you choose, it is not really essential to have the most expensive materials when you are learning. By the same token, there are always headaches with the cheapest pigments, due to poor pigment concentration or random, misleading names, and so inferior outcomes can often follow. Concentrate on getting the bare minimum of primaries plus a few extras in as good a quality that you can afford (rather than a tube of every single colour of cheap stuff.)