Artists use brushes for many purposes–to paint, certainly, but also for applying glue, frisket (a removable masking fluid), ink, varnish, or sealant. Brushes are also good for removing eraser dust, glitter, cat hair, and the occasional cookie crumb that finds its way onto canvas, paper, or journal.
The confusing information about brushes is the number associated with their size. Flat brushes are measured by the width at the ferrule, and that logic makes it easy to guess how large the brush it.
The synthetic brush (black handle, top) holds considerably less water than the smaller squirrel-hair brush.
Round brushes measure from 0 to 24, with 0 being the smallest in the group. They also go below zero, with 0000 being smaller than 00.
Mop brushes are numbered with the same system, but the size of the brush doesn’t equal the size of the round brush. This can be a head-scratcher if you are new to buying brushes.
Tip: A typical squirrel mop #0 equates to a #10 round; a mop #6 is the equivalent to a #16 round, and so on.
Tip: Genuine hair brushes (from kolinsky sable, red sable, fox, squirrel to ox and goat ) use real hair from the animal, (generally the tail). Real hair has ridges and scales and holds water better than smooth synthetic brushes. Natural brushes are also “springier” which means they recover their shape better while in use. Natural brushes are more expensive than synthetic brushes. Often, much more expensive.
Tip: For watercolor, which demands loading with lots of color and water while retaining a good point, use a natural-bristle brush.
Tip: Acrylic paints are alkaline and wear out natural-hair brushes faster than synthetic brushes.
Here is why the natural-hair brush is worth the extra price when you are painting with watercolor–the “fatness” of a synthetic brush doesn’t tell you how much water it will hold. So I did an experiment.
I put all three brushes into water. (I tinted the water blue to make it show up on the photo.) You’ll notice I didn’t just drop them into a jar. Natural-hair brushes shouldn’t be left point down to soak. It ruins the point. And once a natural-hair brush has a bent tip, it’s ruined. Wet, the two larger brushes look about the same size.
The synthetic brush (black handle, top) holds considerably less water than the smaller squirrel-hair brush.
I then pulled each brush straight out of the water, allowed the water to stop dripping, then squeezed each brush over a napkin. The wet ring shows how much water each brush held. The synthetic brush (black handle, above, top) sheds water as you pull it out of the bottle. The smooth fibers don’t hold water like the scale on the hair of the natural-bristle brushes. The natural brushes hold more water.
The water-ring of the synthetic brush is smaller than the water-ring of the smaller of the two squirrel brushes. It’s a big difference; when you are loading your brush with color and water, use the biggest brush for the work. For my money, I prefer natural-hair brushes.
Tip: A cheap brush doesn’t save you money. You will spend more time working with them. They often shed hair on your surface, and that’s difficult to pick out without disturbing the paint or surface.
More information on brush material and sizes.
—Quinn McDonald is discovering a certain joy in using watercolors and watercolor brushes for their lack of control.
QuinnCreative 
Hello! I’m new here on your blog but I had a question. I read on multiple sites that the brushes made from real hair aren’t very animal friendly… I love animals a lot and I don’t want to paint with brushes that weren’t made animal friendly… Do you perhaps know any brands that make good synthetic brushes?
Natural-hair brushes are often the product of some other industry. In other words, natural-hair brushes are recycled hair of an animal already used for something else. Some animals are raised and pieces of their hair are cut, but the animal is not harmed. (Like a hair cut.)
I found an article (and you can find others) about synthetic brushes. Warning: this is an affiliate site, so the writer was paid for writing the article, and might be paid for recommending certain brushes, no matter the results. https://createlet.com/best-acrylic-paint-brushes/
Another suggestion: if you find an article about a topic, don’t ask the author for expert help on another topic entirely. Google “Using synthetic brushes,” make sure that the writer wasn’t paid for an opinion, and finally, try them out on your own. Opinions always vary.
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It’s been so long since you posted this but what brushes (manufacturer, style) are the squirrel hair brushes you used in this post? I love the look of them and would love to get my hands on some if I can find them (:
They are Raphael brushes. Very good brushes at a reasonable price. Available at any decent art supply place.
So, I’m thinking we need to take a brush buying adventure next time we get together! This makes sense now why all my attempts at painting end up looking like Jackson Pollack was my teacher! Yeah, that’s the ticket… It’s not me, it’s the brushes! That works for me! Now, let’s see who sent out coupons this week that I can use for a new brush to play with!
Seriously, thanks for sharing the info. I’ve never been able to figure out what all the numbers or different types of brushes were for so for a long time I just stuck to buying the multi-packs with different sizes.
I have now become obsessed with watercolor, and the squirrel mops that I buy (with a coupon to Jerry’s) are very reasonable and work very well. I believe in buying the most expensive [brush, paper, audio equipment) you can afford in which you can still notice a difference. In other words, if my $8 squirrel mop give me the same results as a $40 sable brush, I’ll go with the squirrel until I get good enough to notice the difference.
Thanks for the info! It is invalueable informaiton, which I did not know.
You are welcome, I didn’t know either, till I looked it up!
A few years back I had some Chinese calligraphy lessons and learned there that you should choose the brush according to your handwriting: if you have heavy hand, use stronger hair like goat, and if you have very light hand use soft hair. Or was it the other way round? Anyhow, I have noticed that it is good practice to intentionally use a brush that makes you use your hand differently. After all, painting/drawing/etc. are not only artistic practices but also techniques that need to be honed. I made endless practice strokes during my calligraphy lessons before I was allowed to write entire words. The teacher, by the way, was a Finn who had a masters degree in Chinese calligraphy from a Chinese university. Not in design, graphic design, visual arts or something like that, but in actual, genuine Chinese calligraphy. Why can’t we study university level calligraphy here in West?
I love Chinese calligraphy, and for a short time, studied it. I loved the practice because you saw how important the brush was, how important your thoughts as you held the brush. I love the idea of firmer and softer brushes. And please don’t crank me up on why we don’t study arts on an advanced level, it will start to fill up my blog. Again.
I seal up my lips and give no words but mum. 😉
This is wonderfully informative. For a someone new to producing art, this is extremely helpful! Thank you!
This question nearly drove me mad, I’d see brushes with the same numbers in all different shapes and sizes. I finally did some research and decided to pass it on.
Well – I definitely appreciate it! Right now I just have craft brushes (cheerfully dropping bristles into the paint), but eventually I hope to graduate up, and I’ve always been overwhelmed in the brushes section of the art supply store.
that’s what made me switch–bristles in the paint. Cat hair was bad enough!