Why Are Brush Sizes as Confusing as a Currency Converter?

How does brush sizing work and where do you start?

Have you every ordered some new brushes online, feeling pretty confident they’ll be the perfect size for your latest oil on canvas creation? After all you spent all afternoon researching them. Only to then be bitterly disappointed when the painting supplies arrive?

		Choosing painting supplies such as a painting brush can be troublesome if you assume each manufacturer sizes their brushes according to the same system.

They were the number you saw in the magazine but have turned out to be either far too small, or far too big. Where did you go wrong?

You aren’t alone. Painting artists struggle with this all the time when deciding how to paint and with what brushes. Selecting the right painting brush size can be very tricky as every manufacturer’s sizes are different. There is no universal sizing system, so a size 10 in one brand can be completely different from another brand.

Confused? Here is a quick painting brush guide to keep in mind next time you visit the art store:

All brushes increase in size depending on the number, so a size 14 will always be larger than a size 12, whatever the brand.

• There are other numbers on the brushes that indicate the series number (often abbreviated to SER). This is usually 4 digits long, for example: SER 6474. This helps to identify a brush correctly when ordering.

• Brushes can come in short and long handles. Short handles are best for detailed work or painting on the flat. Longer handles are best if you intend to stand at the easel.

• The longer the length of bristle, the more flex there is in the brush. A short length of brush hair will appear to be much stiffer and coarser than a longer length–even if the bristle is the same softness of hair. This length is called the ‘length out’ and a long length out was favored by the Old Masters.

Pro painting art tip: When you are next in the art store, flick your thumb from left to right over the edge of the brush. This will give you a feel for the ‘snap’ of the brush. The brush will ‘crack’ when you first flick it, this is the gum arabic that has been used to set the head. It’s advisable to rinse the new brush before use to remove any excess gum arabic.

So the ultimate question is, which size should I buy?

I tend to go by the width of the brush and the length of the bristles, rather than the size or number.

To get started with a small acrylic paintings or oil painting art piece (under A3), I would recommend:

•  Round brush 6mm – 7mm in width with a 25mm length out.
•  Filbert brush 10mm in width with a 16mm – 20mm length out.

Of course, to find the perfect brush for each person can take a little while but this should point you in the right direction. Do you agree? Where did you start in terms of painting brushes? Leave a comment and let me know.

–Will

Will Kemp is an award-winning professional artist from the U.K. He teaches classical painting techniques with a modern approach, so you can discover how to paint & draw in the quickest time possible. Will creates weekly videos at Will Kemp Art School about painting, drawing & creativity.