For a beginner, the idea that a specific brush shape can facilitate art-making is hard to grasp. At least it was for me--I came to the concept much later than many. It's an interesting and useful piece of information that takes a while to learn but knowing brush shapes and purposes should become second nature after a time. And having that information helps in making effective and useful paint strokes. When I began painting, all I knew was the kind of brushes you see in the hands of artists in cartoons--those small, soft, pointed brushes with long handles. That shape is called a "round," named for obvious reasons, but it's hardly the only brush shape an artist needs to understand.
Brush size is another topic that took me a long time to grasp. Most beginners simply paint with one size brush, usually small. Even if the shape is right, though, most people don't use a big enough brush. When it comes to what size is best it's as simple as the old saying that one should begin a painting with a broom and finish with a needle (attributed to Delacroix). That is, it makes no sense try to paint large acreages of canvas using a small soft brush. By the same standard, you can't drop a catchlight into an eye with a square 4 inch paintbrush. For me it has been important to push myself to use the largest brush that I can for the size of my canvas. That way I'm forced to be less picky and more blocky, more shape-oriented when beginning, refining as the size of the shapes decreases and as edges refine. At some point of course, one has to use even smaller brushes to facilitate detail, but that too depends on the kind of stroke, thickness of paint, and other considerations.
So here is a bit about sizes and shapes of brushes.
Brushes are made in sizes ranging from less than 1/16 inch to several inches in breadth. There are probably even people who make brushes with a single hair for very very fine work. Brushes are sold in a numerical sequences by size, but it's hard to figure out just what those numbers mean. For most purposes, brushes about 3/4 inch to 1 inch across have been most useful to me. In the line of bristle brushes I've used that translates into #8, 10, and #12 brushes (by the number on the handle) which roughly translates to 1/2, 3/4, and one inch, but those may vary by manufacturer. I generally paint smaller than 20 by 24 inches, but if I were painting larger works I'd obviously need larger brushes, certainly at the beginning. I don't know what brush numbers mean in different regions of the world although they're always ascending--larger size bigger number. Furthermore, there is no standard for brush sizes and numbers that I know of. So the best I can do is provide measurements. Check those against the manufacturer's listings. It's best to look in art supply stores, so you can actually handle the brushes. It's tougher to check sizes against online images.
The commonest shapes that artists use are flats, brights, and rounds. These shapes are produced using any number of natural and synthetic fibers. Anybody interested should look at Brushes Part 1 for details. Certainly the fiber type can influence the shape chosen. For example, bristle brushes are more often sold in flat and brights shapes.
Flat and Brights
|Brush Shapes, from Turner|
So to summarize, for scrubby strokes, the brights shape offers more control, as it does for short, choppy strokes and brights also allow for use of thicker paint. The flat shape allows long, sinuous stroking with medium to liquid paint.
These brushes are flattened similarly to those above but the tips are rounded (shapes shown in far right of the chart on the right). They come in various shapes from short to extra long. (The extra long filbert shape is sometimes called an "egbert" but I don't know why.) Filberts can be used to lay in a painting because the round contour allows you to turn the brush sideways to draw thin lines or turn it ninety degrees and lay in long, wide strokes. A filbert can help put in long curving strokes such as shadows on rounded surfaces. These shapes are often found not only in bristle brushes but also in the softer natural fiber and synthetic fiber types as well.
This shape is used infrequently, in my experience (middle, top row of chart) but was originally intended to blend oil paint on the support surface. Fan brushes can be gotten in bristles or other fibers of all kinds. Today their use seems to be in decline, but many painters still swear by them for blending.
This shape is made by cupping a tuft of fibers, whether bristle, sable, or artificial, so that there is a round shape and a pointed tip. Brushes with this shape were commonly used for centuries, but often tied or fixed in other ways to a handle or even a big quill, whereas today they are glued inside a metal ferrule. Round brushes, particularly when made of softer fibers, allow for a variety of strokes, particularly when using thinner paint such as watercolor. These brushes often hold a great deal of paint. Variations on rounds can be made with longer hairs and/or more pointed tips.
For me, brushes remain a continuing education. Although I'm now using mostly synthetics, natural hair brushes are still a part of my studio practice. Mostly I use synthetics because they're easier to clean, more forgiving if you forget them for a day or so, and maintain their shape longer. More on that in the next installment, Brush Care and Maintenance.