The paint has four basic ingredients: the colorant, a binder, additives and the solvent.
The term “water media” is used when one takes water as a solvent.
I would recommend buying paint with a high saturation (brilliance) attribute, it gives the whole painting more power and the colours mix more easily with each other. The “artist” paint is more expensive than the “student” paint but it’s worth it. Also take care the paint has a good light fastness, enabling it to shine longer.
Before the 1800 century, people had to make their own paints, alone a timely process. Blue and purple where often associated with royalty as they were hard to make.
Today we usually buy it in either pans or tubes. The standard size of tubes range from 7.5 ml over 15ml to 37ml.Pans are bought in full or half pans. Personally, I would recommend buying full pans at the start, as you can access them easily with big brushes too and you never know how much paint you will need when you start painting, although tube paints don’t dry out.
Important to us is of course the colorant. These are the colour pigments that give us the different colours. Nowadays most are synthetic pigments which are cheaper than biological ones. There is no actual white watercolour, so the trick is to not paint and use the white of the paper, you can use masking tape to stop the paint getting to that area.
When choosing your colours beware that paint manufactures are not legally bound to what name they give a colour and sometimes tend to mislead us. Check the colour pigments on the pans or tubes.
Kicking off, I would not buy every colour available. Two tones of red, blue and green, three kinds of brown and indigo is more than enough. I would try to avoid black as it overshadows all the other colours.