How do I know which brushes to use for my medium?

Watercolours:

As a general rule of thumb the finest hair used for watercolour is Kolinsky Sable, followed closely by Pure red Sable, Squirrel etc. At the moment, there are some excellent Nylon fibres which imitate Sable thus keeping costs low. It’s not just about ‘snap & spring’ which are familiar terms but how the brush strokes the paper. Sable has the advantage of holding a huge quantity of liquid and ‘flows’ when pressed onto the paper. Some beginners/intermediates would choose Sable/Nylon blends or indeed 100% Nylon as the feeling of a controlled strokes is more prevalent.

Oils:

Oils, Sable is a favourite but because of the medium’s heavy viscosity and rapid ‘clogging’ of pigment in the brush head, it isn’t greatly favoured by frequent users as the price is a high one to pay. There are excellent alternatives of stronger Nylon filaments to suit the oil painter and my ranges of Shiraz, Ivory and Chungking Bristle are prime examples. A popular choice for acrylic painters are also Shiraz, Ivory and any of the Golden Synthetic ranges. Masters Choice is also a real treat to use!