It's a great idea to test a new watercolor brush to gauge its performance. Not only will you gain an understanding of how it feels in your hand and if the brush will work for you, but testing a brush also makes it easier to spot a problem before the store's return policy expires.
Of course, the best way to test a watercolor brush is to use it, but oftentimes when painting, it's hard to tell exactly what's going on with a brush. I'll also run an older brush through these tests if I think it's beginning to lose its performance. Using the brush to paint several, specific strokes can help me quickly pinpoint the problem.
Below are step-by-step instructions along with a tutorial video on how to test a brush. I'll also share what to look for throughout each stage of testing and why it might be a good idea to hang onto a junky brush.
4 Ways to Test a Brush
I always run a watercolor brush through four different stroke tests. In no particular order, they are loop, line, wash, and dry brush. Below, I'll give examples and walk through each stroke to help you know what to look for when performing these four tests.
It's important to do these strokes several times to really see what a brush is about. This gives the brush a chance to show its true colors and to make sure a bad stroke isn't operator error. Give the brush a chance to get into its groove, so to speak, or even time to fail. This also allows time to gauge how well a brush feels in your hand while performing these various techniques.
Also, give a brush some leeway according to its abilities. Every brush will have limitations. A larger brush will naturally produce a larger line and looser curves. A synthetic will often have trouble releasing a steady pigment load. What you are really looking for is how well a particular brush performs in your hand, and whether or not you can work with and even enjoy its limitations and benefits.
(Note: Click on each photo to enlarge.)
Watercolor Loop Test
When performing a loop test, I often use a lowercase "l" because the tight curves in this letter really test a brush's responsiveness, but a regular loop will do. This is a great stroke to use in a test because inferior brushes will often splay in the tight curves and/or dump their pigment load on the down or upstroke. This stroke also helps me see how well a brush will pull in two, different directions.
In the photo above, the loop "A" was obviously made by a quality, high-performance brush. The pigment release is smooth and there are no signs of broken, hairy curves which would reveal that a tip snapped apart during that part of the stroke.
In loop "B", you can see how brushes with a high degree of snap like synthetics will really struggle with this stroke and produce broken curves.
Loop "C" was obviously painted with a brush that has serious problems. This brush has lost its performance in a number of areas and can no longer maintain control. Enough said about this one.
Watercolor Line Test
Pulling a line test is more than just drawing a line with a brush. Pressing down halfway through the line and then pulling up, making the line move from thin to thick and back again, is a great way to gauge whether or not a brush has adequate spring and pigment release.
The lines in the first column are what you're looking for... a good line that easily moves between the two extremes of thick and thin, plus a beautiful bubble that smoothly moves from light to dark.
The last line on the bottom left was pulled with a synthetic brush, and you can see where the pigment load released a tiny bit early—more in the middle of the bubble than toward the end where I like to see it. However, this brush performed admirably well for a synthetic.
The second column displays brushes that aren't performing up to par. A brush that has inadequate spring won't be able to pull back together well after the broad stroke. A poor brush will also leave those really round, unstable pigment puddles.
The top example looks pretty good until the fine line; this brush couldn't spring back to a point. At all. In the bottom two examples, the brushes were so poor and splayed so badly when I pushed that it couldn't even paint a smooth, broad stroke. Bummer.
Watercolor Wash Test
Probably the best way to see how to perform a simple wash is to watch the video below, but when doing a wash test, there are a couple of things you'll want to look for. A good brush will have a steady pigment release and be able to easily grab or absorb the pigment bead and pull it down the page.
The washes above are on student-grade paper, so give them some grace, but the wash on the left has slow, steady gradation. Good! The wash on the right has a definite jump in gradation, and you can see where the brush couldn't grasp and pull the pigment bead on each side of the stroke. Bad.
A wash is a basic watercolor technique that all but the tiniest of brushes should be able to perform, so if a brush gives you grief during a wash, it may be time to retire it or use it only for special effects. (See below.)
Watercolor Dry Brush Test
In watercolor, dry brushing is exactly what it sounds like. A brush is loaded mostly with pigment and very little water and can be used to produce a variety of effects from prickly grasses to rippled reflections on water.
To test a brush's ability to work well with this technique, I like to dry brush a few grass blades from the bottom of the blade upward. This often tells me whether or not a brush can pull from thick to thin and carry a decent pigment load when dry, which can be rather challenging for some brushes.
When dry brushing, some of the poorest brushes can produce some of the most amazing effects! Example A was made with a Kolinsky sable; example B with a synthetic, and example C was made with a freebie brush that came with (I think) a craft set. The splayed and floppy freebie brushed pulled out some nicely textured grasses!
Using a bad brush is extremely frustrating, especially for beginners. Using it is also flirting with disaster and may leave you with a puddled mess and a ruined painting. I rarely recommend it, but if you're courageous enough to try it, you might just be surprised!
Video Tutorial: How to Test a Watercolor Brush
I put together a video tutorial so you can learn more about how to test a watercolor brush and see these brushes in live action. If you enjoy this video, feel free to follow me on YouTube where I have more information about this tutorial including a supply list.
I hope this gives you ideas on how to test your own brushes, and the examples prove that quality tools really make a difference. However, a junky brush isn't always a bad thing to have on hand, so make the most of what you have, and happy painting!