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Luxartis flat brushes in detail

The heads of our Kolinsky sable bright flats are suitable for both oil and watercolour paints. Handles are short, in the normal style for watercolour brushes.

Sable tufts give the brushes very good paint capacity with the ability to come to fine 'chisel' edge.

Close-up of chisel edge

This shot shows the edge of wet brush head. The image is enhanced very slightly to emphasise the edge, which is so fine that's hard to pick up on a photograph.

Group of Luxartis flat brushes

The brushes are suitable for block shading and a surprising range of other strokes. More information can be read further down this page.

Luxartis flat brush heads against graph paper

This close-up is set against 2mm/10mm squared graph paper. From left to right, #24, #18, #12, #6, #2.

Brush dimensions

Approximate measurements in millimetres relate to the tuft when wet.

SizeOverall lengthHandle max. diameterTuft lengthTuft width at ferruleTuft width at tip
#2177572.51
#61827964
#122129.515116
#1823014211913
#2426021272820

What can I do with a flat?

This section is written from the perspective of watercolours. For the sake of comparison, we shall discuss a good quality #18 synthetic sable flat alongside a Luxartis #18 Kolinsky sable flat.

Both are far more refined than a flat wash brush. The tufts are good at holding their shapes and tips come to a distinct edge. They are suited to blocking in areas with precise boundaries.

Block shading within precise boundaries

That isn't their only use, as you will see further on.

Hair qualities compared

When we refer to synthetic hair, we mean synthetic sable, which is finer and softer than man-made imitations of other natural filaments such as bristle.

Synthetic sable is a low-cost alternative to natural sable. Real sable does have clear advantages but synthetics don't lose out entirely.

Man-made filaments are more robust in the face of rough treatment and aggressive chemicals. You can use them with just about any paint and surface. Being fairly inexpensive, you don't have to worry about wearing them out quickly. A well-made synthetic brush is adequate for many tasks.

Sable is a natural hair, with Kolinsky being a superior grade that commands a price premium.

It has special qualities not equalled by synthetic imitations. Superior paint capacity, points and feel set it apart.

These properties have long made sable the best hair for watercolour brushes. It is also used in some quality oil painting brushes.

Please note that although the Luxartis flat sable brushes are suitable for both oil and watercolour, Luxartis round pointed brushes are intended for very thin mediums such as watercolour or other diluted free-flowing paints. They are not stiff enough to push thick paint around.

Sable can be used with acrylic paint. This medium is very alkaline and will degrade a natural hair more quickly than traditional oils and watercolour. If you paint with acrylics and brush life is important, use synthetics or coarser natural hairs, or at least use them when sable isn't really needed.

How they perform

The shape of synthetic and sable flats is such that it is possible to paint up to an edge in a controlled and accurate way. Because of this, their most obvious use is block shading.

Plenty of people use synthetic flats quite happily, especially if they haven't tried something better. Only when you handle a sable brush alongside a synthetic does the difference stand out.

Laying down wash, the synthetic feels a little harsh and unnatural. It makes a slight plastic-on-paper noise as it rides over the texture. Pigment is soon exhausted. It isn't an unpleasant experience, but neither is it very satisfying.

Switching to sable, not only does it feel smoother, finer and more luxurious as it quietly glides over the surface, but the quality of the paint is different. The brush holds more pigment, releases it more smoothly and covers more area.

Synthetic gets the job done, with more visits to the wash dish, but sable does it better and gives tactile pleasure in the process.

Other techniques

Synthetic and sable flats are not limited to block shading and broad strokes.

Each hair tapers so that is thinner at the tip. This is more pronounced in genuine sable – that's why the sable brush heads curve in towards the tip. In a round brush, in conjunction with skilful making, the taper leads the tuft to a fine point when wet. Even a big sable brush will hold a good point.

In a flat brush, the point extends sideways to form a fine edge, often referred to as a chisel edge.

Sable does this better than synthetic filaments. A synthetic may be good, but sable is distinctly thinner.

Turning the brushes sideways to see their profiles, although the quality of the edges can't be made out here, it is easy to see how much more belly the sable has. And yet its edge is finer. You're also seeing part of the side of the sable brush, so it isn't quite as plump as it seems – perhaps about two thirds.

Flat brush heads side view

The chisel edge can be employed to good effect. Straighten it up on the palette or scrap paper, then gently dab it vertically. The result is a fine and fairly straight line. This can be repeated to build up a longer line, lots of parallel lines, or semi-random overlapping lines to make a textured effect.

Brush-edge lines have a different quality to ones drawn with a rigger or round. They are fine, but often have little irregularities, perhaps tiny breaks, depending on how you mix the paint, the nature of the paper and the way the brush is handled. This is an advantage when you don't want things looking too perfect. It adds character and visual interest.

Line samples from a flat brush Lines with the #18 sable brush
Top: repeated dabs of the chisel edge.
Far left: short dabs joined together, heavy and light paint loads.
Left: lines obtained by dragging the whole edge sideways, and using the corner alone

Rigger-drawn lines are naturally smooth and flowing. Their straightness, or adherence to the intended path, depends on the steadiness of your hand. The same is true of lines obtained by dragging a flat sideways. It takes skill to execute a long line without a pencilled guide and not have it wander a bit.

Lines made by dabbing the flat brush edge are easier to keep on track. Don't try to steer them round sharp bends though.

So owning flats doesn't make riggers redundant. Both have characteristics that might lead you to favour one or the other on different occasions.

Other strokes you can execute with a flat brush are point-like ones obtained by using the corner. They aren't as fine as the points possible with a round pointed brush. Neither are the lines you can obtain by pulling the brush from the initial point. Still, these points and lines serve on many occasions.

Dot samples from flat brush Magnified image of a variety of dots produced with the corner of a sable flat

Dabbing the edge with a bias to one side produces shorter lines which, by varying pressure and paint load, can be significantly thicker at one end.

Edge dabs of different lengths
Edge dabs of different lengths (magnified) produced by angling the brush towards a corner. Most of the irregularities are caused by the paper texture

Taking the block shading, lining and pointing abilities together, the flat brush is far more versatile than you might have expected. These capabilities improve with practice and are not the limit of what they can do.

Round pointed brushes are still the classic tools for watercolour, but as you can see, there are other ways to paint and a technique based primarily on flat brushes can be developed. Some artists use rounds alone, a mix of the two, or produce entire paintings wholly with flats.

There is no right or wrong. If your brush choices are comfortable and work for you, they are justified no matter what anyone else does.

Bright vs. one-stroke

Flat brushes can have longer hairs, and these are called one-stroke brushes due to the extra paint capacity this brings. The Luxartis brushes have shorter hair in the pattern known as 'bright'. While this reduces paint capacity, it's still very good because of the sable. And the brush is stiffer, which gives better control.

Are Luxartis flats wash brushes?

Strictly speaking, no. A dedicated wash brush will typically use a cheaper hair that lacks sable's spring and point. A good wash brush will carry a lot of fluid and is mainly for covering larger areas with water or wash. It can be used for some interesting painting techniques too, but is not by nature a very precise or controllable instrument.

Sable flats can be used for area washes, but don't carry as much fluid as a specialist wash brush of similar size. They are, however, precise and controllable.

So although there is some overlap in the roles of the two brush types, each has its strengths. You probably wouldn't use a wash brush to block in the mass tone of a building, but a sable flat won't cover a big sky or sheet of paper with the ease of the same size wash brush.

All content © 2008 Luxartis Fine Art Products