Classification of paint brushes

The artist brush is the most basic tool that the artist uses to realize his concept on paper, canvas, cloth and many other surfaces.
It is structurally divided into three main parts: the handle(for holding), ferrule (or capsule)that holds the hairs and the hair tuft, which is the part of the tool that interacts both with paint/ink and the surface.
The handle is generally made of solid wood from deciduous trees (oak, birch, beech, etc.), sometimes synthetic materials (e.g., plastic) are used. There are exclusive brushes with ivory handles, some minerals, precious stones etc.
The hair tuft of the brush is formed in certain size and a predetermined shape, with natural hair (tiger, pony, goat, badger, columns, bristles, etc.) or synthetics.
There is a division of the hands and the exhibition of the hair (ie the length of the hair in the hair bundle). Typically, the major manufacturers of brushes produce three main types of hair in the hands of the exhibition of the same size: an elongated, standard and shortened. This differentiation allows different work during a session of painting. Brush with a short exhibition conveniently perform short strokes or lighten the exact right place, washing off the ink particles from the texture of the paper. Brush standard averaged exhibitions usually performed most of the work. This brush is universal. And finally, the elongate brush insert is intended for drawing the long thin lines of constant width.

The most universal brush type is the "cartrige". The ferrule, or "cartrige"  is a round metal part that holds the bristles together and attached to the handle of the brush. The base coat is fixed with adhesive and sealant is further applied. The ferrule must adhere to the handle, they are bonded with a special machine. When some hairs are constantly falling off, this usually means that there was not enough glue, or it was badly applied.

The shape of the cartridge brushes can be divided into two main groups: round (the cross section of the cartridge at its end iscircular) and flat (the cartridge is where it holds the hairs).

round bristle brush

Round brushes - perhaps the most versatile of all the brushes. Depending on the tilt and pressure it is possible to apply paint and draw lines as constant and variable width in a particular area, to carry out broad, thick strokes or exactly the opposite - the thinnest line with its very tip.
The round brush is ideal for drawing as it can be used for fine detailing.
A specific example of round brushes are the font and line brushes.  gives a definite shape, ensures the safety of the hair bundle and connects it with a pen. It is usually metal but may be made of other materials. Most are easy to use, practical, reliable and attractive
weldless holder.

 Flat brush

flat brush, parts of the brush

The flat brush, unlike the round, is more elastic, thereby becoming indispensable when dealing with large areas of the surface of the canvas or paper, or when applying a wide flat stroke with constant width (depending on the rotation of the hand when moving the stroke thickness can be varied too) .
They are very convenient for representing the pictorial elements in nature such as land, grass, leaves, as well as architectural compositions of urban landscapes and anything that requires a relatively precise outlines. This brush is characterized by that the capsule is flattened at the end, allowing the hair to form the desired flat plane - hence the name. Thick, long hair flat brush allows you to keep a sufficiently large amount of paint.

Bright brush

Type of flat brushes, that have a shorter hair tuft, giving extra firmness to the stroke. This ensures high quality flat strokes. Thanks to the short hair, with the help of contour brush it is very convenient to make the outlines of drawing or, for example, graphic works and can also be used to create smooth color transitions.

Cat's tongue 

This brush type, a variety of the flat brush, got it's name due to the special shape of the hair bundle - a dome or oval shaped. It is versatile and it allows, depending on the position and inclination towards the working surface (canvas etc.)to perform strokes, characteristic for both circular (at a perpendicular position to the surface), and for the flat brush.

Sword brushes 

Type of flat brushes, that have relatively short hairs, and characterized by the fact, that the hair is cut at an angle. This allows you to apply a very accurate (depending on the angle and position of the hand relative to the working surface) strokes. The uneven brush tip would allow the artist to quickly and easily change the volume of the paint that is loaded, depending on the task chosen. This feature allows you to confidently and accurately perform the color transitions in the uncomfortable (hard, narrow, small) portions of the picture.

Stencil brushes 

Stencil brushes are a kind of round brushes that get their name from on their main purpose (apply an even layer of paint over the stencil). The main difference is in the shape of the tip of the hair bundle. Unlike conventional round brush, that has a tip at the end (which allows you to perform sufficiently thin lines) at the end of the stencil brush, the hair is cut flat. The paint is applied with this brush on a work surface not in horizontal strokes, but with vertical pressings (sometimes light "hits" or taps). However, these brushes are also suitable for glazing, and to apply layers of paint in a free manner.

Mop brush

Mop brushes are very wide flat brushes, intended primarily for application of broad layers of paint in one stroke. Mop brushes are able to hold a lot of paint, making it possible  to to cover a large area with a few brush strokes. Dry brushes can be used when working on top of another wet paint layer, to create such effects as a blur or to soften some edges. Usually the mop brushes are used in watercolor technique, but may also be of great use when working in oil, gouache, and other types of paint.

Rigger brush

This is a kind of round brush, that has
very long hair. This form and the length of the hair bundle the main purpose of the brush (hence the name) is the ability of thin straight lines without reloading. Very handy brush for graphic works, but using to its full potential in the process of painting, it takes much practice and experience.

Liner brushes 

This is a kind of round brush, whose shape and properties are similar to the font brush, but unlike the latter have shorter hair lenght. They can apply really thin and precise lines.

Fan brush 

Fan brushes are a kind of flat brushes that got its name due to the special shape of the beam, that looks like a fan. Due to this they are very convenient to perform sophisticated color mixing, soften the contours and create contrasting textures . Just one swab allows you to put a lot of fine lines, for example, when drawing grass, etc. Working with it requires a certain skill.

There are three main characteristics that must be considered when assessing the quality of a brush. You can easily separate the quality brushes from cheap low-quality fakes. There are three main characteristics that make a good artist brush:
1. The ability of the hair bundle to form a sharp tip. This indicator is very important, because in the creative process one often needs to apply very precise strokes, fine lines, very fine detail etc. If your brush will is not able to perform these tasks, because edge of the beam is too thick or the hairs are scattered among themselves, then it simply hinders your work.
When pulled up from the painting surface, its hairs should retake their original form and be ready for the next stroke.

2. The elasticity of the hair bundle. For quality brush strokes, it is important that the hairs have certain elasticity. This allows various effects to be achieved, that cannot be easily done in another way, e.g. scrubbing in etc.

3. Control of the fluidity of paint. When working with dilluted paint, it should flow from the hair brush with the desired consistency, in a controlled manner.

Few tips for choosing a brush.
First determine which technique you are going to work in, meaning what paint are you going to use. The thicker the paint, the harder the hair of the brush should be. For watercolor, the brush from squirrel hair is suitable. For gouache - synthetic. For acrylic - synthetic, Kolinsky brushes, for tempera - synthetic, bristle, badger, oil - bristle,  and other synthetics. Of course, your choice should mostly be based on personal experience and preference.

Each brush has different size and mark-making properties. Typically, the size is denoted by a number indicating the diameter of the ferrule. However, this marking is not always universal, especially if the brush manufacturers are from different countries. Therefore, choosing a brush pay attention not only to the number, but gauge the size "by eye" to see if the brush suits your needs.

So, now that you have decided on the material and the size of the brush, you should check its quality. Start with the ferrule. It should be evenly and firmly fixed to the handle, not hanging out and not sliping or moving on it. Such a brush will be uncomfortable for work, it will be very difficult to perform the desired shape and stroke with a predetermined pressure. In addition, during painting will the brush will shed hair that are left on your canvas/paper.

It is also important to check the elasticity of the brush. Press it against your palm, to see how hard/soft it the hair is, and if the brush retains its shape after applying pressure on it.

Moisten the brush with water ( wait for a while until the hair is fully saturated) and lightly tap your finger on the handle. A good round brush tip is to sharpen. Try now without departing from the surface to draw Arabic numeral "eight" (if there is paper,try on it, if not - on your palm). If the line has a smooth, uniform thickness without breaks and spray, that means  you have a good quality brush. Additionally, note the individual hairs in the bundle. The hair should have natural ends and not be cropped.

Care for your brushes.
Brushes require careful attitude. Rough handling (e.g., roughly pressing a watercolor brush in the bottom of the water tank) can easily lead to damaged brush, sometimes even making it unusable.

Do not leave the brush in the water or medium, this will bend the hairs and change the shape of the hair tuft.  After finishing work, the brushes should be thoroughly cleaned of paint and put in a container (jar, vase, round box, etc.) for storing brushes, with the hair side up. The accumulation of dry paint on the hair of the beam near the ferrule and inside it, significantly reduces the life of the brushes, so after painting session always thoroughly clean the brush.
After working with watercolor and gouache, rinse the brushes well with lukewarm water, making sure that there is no paint residue left.
If you are working in acrylic or oils, keep in mind that poorly washed solvent will accumulate inside the ferrule, and it can dissolve the glue inside, which leads to hair loss and a worthless brush.

Keep the brush in a dry place protected from moths to avoid damage to the hair, and in order for the hair tuft to retain its shape.

All brushes differ, depending on the type of their hair. Here are some examples of the most common hair types.

Natural fiber brusehs

Best group of brushes for watercolor. Squirrel hair retains its shape, does not break, perfectly absorbs and releases moisture, and are easy to clean under running water. Squirrel brush allows you to draw smoothly without uneven strokes and overlay blurry spots. This brush is indispensable when working in glazes. The very soft hair allows you to overlay one layer of paint on top of the dried one, without damaging it. However, this brush will not work if you want to leave a strong brushstroke by pressing the paint in the texture of paper/canvas, as squirrel hair is relatively soft.
The best squirrel hair is obtained from the Siberian squirrel.

Bristle brushes

Those use natural hair pig. • Top quality bristle brushes are those that are made from the hair of Chinese angkingskogo hog. These hair bristles are hard and resilient. It is perfect for use with thick paint (eg, acrylic, oil).
However, if you decide to work with a bristle brush in watercolor, be advised that this hair is hard enough to not only destroy the paint layer (operating glaze), but also damage the basic structure of the paper! So please be careful and cautious.

Brushes made ​​of synthetic hair

Thanks to the innovation in technologies a unique synthetic fiber has been created - polyester.Special technology allows it to have the necessary form, identical to the hairs from natural origin. Synthetic hair show excellent quality -fluidity, elasticity, rigidity, all of the qualities needed for artist brushes.
It is important to note that the synthetic brushes, unlike natural, are of different stiffness (designation: stiffness icons 1 to 4) and the elasticity depending on the purpose. Very hard (4, exceeds the elastic stiffness of the hair bristles), hard (3 is similar to bristles) and average (2, similar in stiffness with column) synthetics superbly suits working with acrylic and oil, and the soft synthetics (1) are suitable for gouache.
Note that the synthetic hair brushes are readily available for purchase and are much cheaper than their natural counterparts, although still inferior to them in some ways.