If you’re buying artist quality paints, you’re usually buying them individually. So which ones to choose, and which brand?
The answer is to ignore the paint colour name and choose by pigment (the colour ingredient of the paint). All quality paint manufacturers will list the pigment components of their paints, and many paints are a combination of pigments – so there’s no need to buy them if you can mix them yourself. This way you can choose the colours that suit your painting style.
Although there are easily 1000 paint “colors” available across all watercolor paint brands in the USA retail art market, all these “colors” have been manufactured with just 100 or so generic pigments or colorants. – Handprint
So how to choose? Take a look at handprint.com, a staggeringly comprehensive guide to watercolours. On this site you will find:
As for where those pigment codes come from, the letters just indicate the colour: PB = Pigment Blue, PO = Pigment Orange, PBr = Pigment Brown (see about.com)