how to test watercolor brushes
The brush is a very simple tool, and its use varies greatly across different styles or methods of painting. Your criteria for what makes a good brush, and the kinds of brushes you will need, may be quite different from another artist.
the good brush
What makes a good brush? This is like asking "what makes a good tool?" The obvious response is, a tool for what purpose? Painters use brushes in a variety of ways to achieve a variety of effects: the "best" brush will be different, depending on its use.
Overall, artists will find very good quality in the moderately to expensively priced brushes available in the art materials market today. The "house" brands available from large art retailers such as Cheap Joe's, Daniel Smith, Dick Blick, Utrecht or Winsor & Newton (among others) are often equal in quality to the best available brushes: but this is because large commercial brush manufacturers such as daVinci or Escoda actually make the brushes under private label.
Ideal Brush Qualities. Most watercolorists doing most kinds of watermedia paintings have found these brush attributes are highly desirable:
Clean shaping. Once the tuft is thoroughly wetted and filled with water, the bristles should snap immediately to a clean profile. Flats should come to a perfectly even, bevel edge, rounds to a needle point, and there should be no stray or splaying hairs along the side of the tuft. (To do this, hold the brush in your normal grip, then shake out the water by snapping the brush in a single sharp, down and up movement of your forearm.)
Large capacity. The brush should hold a generous amount of paint or water. Capacity varies with the size of the brush, the type of brush (shape of the tuft), the type of hairs or fibers used and the way they have been cupped, but comparisons with other brushes of similar size and construction will reveal significant differences in carrying capacity. In larger brushes you should be able to complete a fairly long brushstroke as a single gesture, without going to the palette for more paint.
Consistent release. When the brush is charged with fluid (either pure water or moderately diluted paint), and applied to paper at a 45° angle with gentle pressure, the brush should release paint in a steady, continuous flow. The brush should show much the same release characteristics regardless of the amount of paint it contains (except when the brush is fully charged with paint or almost thirsty). The brushstroke should not start or end with a "kiss" or puddle of excess paint that creates a small backrun when it dries. (Most brushes will do this, especially when fully charged with diluted paint, but some brushes do it more than others.) The density of the stroke should be even across its entire length and width, and visible streaks should appear only when the paint in the tuft is almost depleted or when the paint is only slightly diluted.
Release variations across brush angles. The amount of paint released from the brush should increase or decrease as the brush handle is held at a more vertical or sideways angle to the paper or as greater or less pressure is applied during the stroke. Holding the brush handle vertically to the paper should produce a juicy release of moderately diluted paint; holding the brush handle almost parallel to the paper surface should produce a dry, scratchy release of thicker paint. All types of release should be easy to control and you should be able to get a specific texture repeatedly, at will.
Wicking. When shaken out or blotted to a thirsty wetness, the brush should wick up diluted paint or water from the paper. (It should wick up at least half its total wet capacity of liquid.) The tuft should lift nearly all its capacity from the paint well without excessive or prolonged dripping.
Crisp lining (edging). When moderately charged with paint and using only the point of the tuft, a round should be able to render a crisp thin line and a variety of very small stippling or hatching marks. A flat should be able to "chisel" repeated, even line segments (made by holding the brush handle vertically and tapping the paper lightly with its edge), as well as clean edges and sharp corners. When several marks are done in a series, they should be nearly identical to each other and should be easy to align or position accurately, yet they should visibly change with the charge of the brush (the amount of paint in the tuft), the pressure applied, and the speed of the stroke.
Tuft spring. The tuft hairs, bristles or fibers should flex to track changes in the direction and pressure of the brushstroke. As the brush is pressed into the paper, they should bend together; as the direction of the stroke changes, the hairs or bristles should shift together; as the brush is lifted from the paper, the tuft should come away with a clean profile, ready for the next stroke.
Variation in brush marks. The brush should allow you to create a great range of nuanced gestural marks depending on the charge of paint, paint dilution, brushstroke speed, brushstroke pressure, angle of handle and paper finish. Each type of brush will produce its characteristic marks, but all brushes should show an interesting range in the marks it can make.
Balance. The brush should rest comfortably in the hand. The handle should not be too thick or massive to produce delicate strokes, but thick enough to ensure control and stability during the brushstroke. The center of balance of a moistened brush should be between the bottom edge of the ferrule and the widest swelling of the handle. The length or shape of the handle should not force you to hold the brush in an awkward position. (Note: in general, the optimal grip for a watercolor brush is closer to the ferrule than it is for an oil brush.)
Hair quality and cupping. In kolinsky or sable brushes, the outer hairs should be somewhat softer, shorter and more flexible than the hairs at the center of the tuft. The tips of the hairs or the overall shape of the tuft should not appear to have been cut or trimmed in any way. The hairs should not be too coarse and the thickness of the hairs should be proportional to the size of the tuft (thinner hairs in smaller tufts). Color is less diagnostic (hairs can be dyed), but the hairs should have a clean, glossy, healthy appearance, a gradual darkening from tip to belly, and should resist stains. There should be no broken or bent hairs whatsoever. In all natural hair brushes, the tuft should show high quality cupping when clean and completely dried. The individual tuft hairs should come to a needle point when examined under strong magnification. The ends of the hairs should form a perfect convex surface.
Ease of cleaning. Pigment should rinse easily from the tuft during use, and clean out completely with a thorough rinsing and blotting dry with a clean paper towel. (Always blot a tuft by folding it inside a clean paper towel and gently pinching the tuft around the sides with your thumb and fingers, shaping the tuft as you go; do not squeeze and pull on the tuft as this can loosen individual hairs.) The hairs or bristles should resist staining from phthalocyanine or other strong staining pigments; the stains should disappear completely when washed with brush soap. The pinch of the ferrule should be firm enough to prevent pigment particles from accumulating at the base of the tuft where they are difficult to remove.
Resistance to moisture. The wood handle should not warp, swell or crack after long exposure to water; the ferrule should remain tightly secured to the handle. The paint finish on wood handles should not crack or chip.
Shedding. If properly used and cared for, the tuft should not shed or lose hairs during painting after it has been used a few times or during the first week of use. (The loss of a few hairs at first is normal in most natural hair brushes but is unusual in natural bristle or artificial fiber brushes.) Any shedding after that point indicates the hairs were carelessly tied and trimmed before assembly with the ferrule and handle, and/or that the ferrule is inadequately crimped around the tuft. Some shedding may be tolerated in squirrel mops and goat hair Japanese brushes, but even here it is a matter of degree: less is better.
Durability. The brush should withstand long and frequent use. Brushes used several times a week should retain their physical integrity for at least six months in synthetic brushes and for at least two years in natural hair brushes. The bristles should retain their characteristic spring, shaping and release, and should not splay, break or fall out. (This assumes you do not have a punitive brush technique that includes using the brush to soften pan paints or dried out palette paints, aggressive splaying or pounding of the brush on the paper to produce paint textures, letting the brush dry out with paint in the tuft, etc.)
Value. Across the time you use it and the uses you put it to, the brush should be the cheapest investment you make in art materials. A $150 kolinsky round should last for several years of daily use. A $2 synthetic should save all your other brushes from destructive wear in texturing, applying resists, softening pan paints, etc., and should be easy to replace when it wears out.
Elegance. After much use and in recognition of their distinctive contribution to their work, artists develop a preference and even a great fondness for certain brushes. This is the final test of its quality. The brush's natural elegance, functionality and simplicity plays a significant part in this passion, but the key is that the brush just "works" for what the painter wants to do.
Realistic Brush Comparisons. No brush will meet all these criteria exactly and different types of brushes meet some criteria better than others.
The most useful way to evaluate a new brush is by comparing it to another brush with the shape shape and size of tuft. Ideally, the type of hair or fiber should matter less, but kolinsky and sable brushes generally set a higher standard on all points than squirrel, bristle or synthetic fiber brushes.
To evaluate a new brush, simply compare it stroke by stroke with the best brush of the same type and size you currently own. It really is helpful to use the two brushes at the same time and on the same sheet of paper in the same tests of pointing, capacity, release, expressive marks, comfort and ease of control. Differences between the brushes will be immediately obvious.
As you select brushes for your use, you will discover that your brush preferences change depending on the kinds of painting, and painting effects, you want to do. Don't be surprised to discover that your brush preferences change as you evolve as a painter.
a basic brush set
The standard recommendations for a basic and versatile brush selection most often come down to these five brushes:
a small sable round (#2 to #4 is a good minimum size) for detailed textures, lines, hatching, and small forms or figures
a medium sable round (#6 to #8) for small paintings, small paint areas, medium textures and rendering medium sized forms
a large sable or synthetic round (#12 to #14) for rendering large irregular forms, charging washes, wicking up excess liquid
a small acrylic flat (1/4" to 1/2") for sharp edged details, corners, and crisp edged texturing or stippling; also good for scrubbing or moving small areas of paint already on the paper (for example, to remove mistakes), and for lifting large amounts of paint from dry pan paint cakes (for example, to mix a wash)
a large natural hair flat (3/4" to 1") sable, squirrel or a blend of bristles, for medium sized washes and glazes
a medium squirrel mop (#8 to #12) for laying washes, prewetting the paper, wicking up excess paint or water, and subtly adjusting the density or texture of wet paint.
Though it's not a brush, a natural sponge (a sea sponge or a block cellulose sponge, not the plastic kind) is very handy.
All the brush sizes quoted above are relative. The size of brush that is most convenient for a painting depends on the format or dimensions of the paper you are working on and your painting style. I think the recommended range of brushes is most suitable for work on paintings using a half sheet (15" x 22") watercolor paper or medium sized watercolor blocks (10" x 14" or so). (For the smallest paintings the large flat or round doubles as a wash brush.) However, the "dash and splash" style of the California scene painters and their contemporary imitators (such as Mel Stabin) prefer larger brushes across the whole range of brush marks: their sky wash brushes, for example, are typically 1-1/2" to 2" wide and their largest natural hair rounds are a #16 or larger.
You may want to start with synthetic bristles in all these brushes, as synthetics are relatively inexpensive yet can be very well made. Once you become accustomed to these brushes after a month or so of painting, then it's time to begin replacing them with natural hair brushes. You will immediately see the contrast between the two types of brush.
The argument that you should buy natural hair brushes at the outset is based on the idea that they will contribute significantly to your painting experience and will guide you to a more rapid and reliable improvement in your painting skill. This is believed to more than offset the 100% to 1000% increase in price, depending on brush size and quality, that the choice of natural hair brushes entails.
My opinion has two parts: (1) the quality of brushes today is generally good, so if poor brushes deter you from painting, then you should be doing something else with your time; and (2) there is real value in using synthetics first so that the merits of natural hair brushes become obvious in contrast. If you start out using natural hair brushes, you will have no concept of brush value in terms of the price you pay for the brush.
Once you decide on the brush types and sizes you need, you have to buy them. This is not as straightforward as it seems.
Obviously, you can't test brushes ordered from direct delivery retailers. It's very valuable to find a local art store with a good range of brushes, and educate yourself with a half hour of browsing with the store owner or senior retail assistant. (If possible, talk to the owner or brush buyer, because he or she is aware of the distributor discounts and quality considerations that motivated the choice of the brush lines.) Best is to visit two or more stores with different brush selections. If there's no reliable art store in your vicinity, schedule an art shopping morning or afternoon into your next vacation or business trip to a large city. (Pearl Paint and New York Central were regular visits on my business trips to New York.)
When you are in a retail art store, the most basic courtesy is: don't touch the brush tuft with your fingers. The tuft will pick up oils and dirt from your hands that you pass on to the eventual owner. If you want to test the snap or consistency of bristles, listen and feel as you stroke them across the back of your hand.
Many authors suggest that you examine brushes in a store with the bristles wet. This is impractical advice, as most stores won't allow you to wet and poke their merchandise, and many brushes come "wrapped" in a hard coating of starch or gum arabic. Even so, it won't hurt to ask; the store may be able to provide brush samples with the starch or gum coating already removed.
In the end, you have to choose a few representative brushes from a brand you want to try, buy them and put them to use. This is the only way to discover if you like that brand of brush or not. If you like it, try more brushes from the same brand. If you don't like it, relegate it to punishing work scumbling, application of resists, loosening paint in a dry pan and try something else.
Natural hair rounds (and some synthetics) usually pass through retail stocks with a coating of starch or gum arabic on the tuft, to protect individual hairs and display the pointing of the tuft. To remove the manufacturer's starch coating, first wash your hands, then wet the brush for a minute or two under a stream of lukewarm water. Then apply gentle pressure to the tuft by pinching with your thumb and index finger, working around all sides of the tuft. Continue this until the tuft separates and flexes at the ferrule. Gently pinch with your fingers the straggling stiff tufts of hair to remove remaining starch. When all the starch is gone, continue rinsing for another minute or so. (Often dissolved starch will remain in large rounds even after they seem thoroughly cleaned, so you have to let them dry and then rinse a second time.)
To test the brush's shaping, saturate the cleaned tuft under running water, then gently shake the water out the brush. To do this, hold the brush handle vertically, with the tuft down, then snap your hand down and rapidly upwards from the elbow the same arm movement you would use to crack an egg, but with much more force. Do this repeatedly, checking the shaping of the tuft each time, until no more water is released. The bristles should come to a needle point (for rounds) or a straight, unbroken edge (for flats) on the first snap if not, consider how many snaps (if any) are required for pointing to happen. There should be no stray hairs around the sides of the tuft.
Look at the shape of the brush: is it fat in the middle, or slender? Is the tuft long or short? Is it large or small compared to other brushes of the same numerical size?
Consider the heft of the brush. Is the brush balanced in your hand? Does it feel comfortable to hold?
Next, test its carrying capacity and release. How much water can you shake out into a dish or palette? Hold a "thirsty" brush horizontal, and measure how many drops of water can you can add to the tuft before water begins dripping out the bottom. Mix up a medium solution of ultramarine blue and a second of burnt sienna, and make a single long stroke, or repeated strokes, with a single charge of either paint. How long a wet stroke can you make before the brush runs out of paint? Examine the strokes to see how evenly the brush releases paint in a stroke. Are there puddles of paint at the beginning or end of the stroke?
Next, charge the brush with the other paint and make a second stroke. When does the paint color begin to shift back to the previous paint? If this happens early in the stroke, it means the brush is not releasing the full reservoir of paint. Finally, rinse the brush lightly with water, and paint more strokes: when does color reappear in the stroke, and how concentrated is it? This will tell you how easy the brush is to rinse out as you paint.
Next, make many random doodlings and brush stroke variations. Use the brush in as many different ways as you can. Use it drybrush and very wet, wet on dry and wet in wet, thick strokes and thin, impasto and washes, straight and curved lines, dots and hatching, anything you can contrive.
You will also probably have favorite painting subjects or forms that appear frequently in your work (flowers, trees, faces). Use the brush to paint these forms using only the ultramarine blue and burnt sienna in a two colored (warm/cool) painting. You're testing the brush, not making a masterpiece, so work briskly and watch how the brush behaves as you work.
Then look at the whole assortment of marks and paintings. Are they pleasing or not? Are they really different, or do they look like variations on the same dumb daub? Can you see specific edge and line attributes (crisp, flowing, nuanced, surprising) that you want? Did you enjoy using the brush? This is the basic brush personality test that determines whether you and the brush are going to get along.
But it's not the final test. That comes when you pay attention to how you use brushes as you work. You'll find that your rational selection procedures don't always serve your instinctive reach for one brush rather than another. In some cases these instincts are just habits that new brushes will allow you to break. In other cases they reflect the goals of your painting and are fundamental to your style or working tactics. And you'll discover deeper aspects of the brush: how well it holds its shape over the long run, how it stands up to rough treatment or neglect, and how it rebounds from tough pigments like the phthalos or chinese white.
At this point, it's simple (too simple!) to go back and get more brushes different sizes, different brands of the type you prefer. But by this time you'll buy new brushes with the awareness that your choices depend as much on your capabilities and desires as on the objective structure of your tools. Art is as much about self discovery as skill.
The brush is an extension of your hand and it's your hand, not someone else's. You can buy the best brushes on the market, but if they don't behave in the way you want and are comfortable with, you'll be unhappy. Use what makes you happy.