If your paint isn’t behaving the way you want, don’t blame your hand just yet—blame your brush.

Most painters don’t think much about their brushes beyond the size. But classical painters? They obsessed over bristle type, shape, spring, and even hair direction. Not for the sake of being fancy—but because every brush leaves a mark, and those marks matter.

Let’s explore how they thought about brushes, and how to choose the right one depending on the job.

What Classical Painters Knew About Brushes

And why not all brushes are created equal.

1. The five fundamental functions of a brush

One single type of brush can’t paint everything. Each brush has a different kind of touch, you want to use this at your advantage and not limit yourself.

Brushes must perform five fundamental functions:

Tracing means that the brush mark needs to remain visible after it is applied. Like drawing with a pencil.
Flattening means that the color is spread evenly on a given surface, like a house painting roller brush.
Blending implies merging the paint newly applied to the previously applied fresh paint. This function is comparable to what a blending stump does.
Spreading involves extending a small quantity of paint on a large surface. Like what you’d do with a broom, pushing the paint around.
Thickening implies bringing body to the paint layer with a generous amount of paint, called impasto, like what a trowel would do.

Each brushstroke should serve a certain function, ask yourself which one before picking up your brush.

2. Bristle vs. Hair – The Stiffness Spectrum

Classical painters had a full range—from stiff hog bristles to soft sables—and they picked each one with purpose.

Stiff bristle brushes (like hog hair) are perfect for sculpting thick paint, laying in bold shapes, or pushing paint across a textured surface. They "grab" paint off the palette and deliver energetic brushstrokes. They’re a favorite of those who prefer a thick, alla prima style, very snappy and energetic.

A snappy bristle brush leaves texture marks in the paint but carries more paint.

Soft brushes (like mongoose, soft synthetic or sable) are better for blending, glazing, or laying down clean edges. They create that refined look you often see in skin tones or atmospheric backgrounds. They’re usually preferred by tight painters who want a high level of detail and soft, carefully blended transitions.

Soft hair brushes don't leaves textures mark but hold less paint.

🔍 Why it matters: Using the wrong stiffness can make your paint skip, drag, or go mushy. Soft brushes can’t handle thick paint. Hard brushes can ruin a delicate glaze.

▶️ TRY THIS: Use a stiff brush for your first layer, build it boldly with thick, opaque paint, then switch to a soft one for blending and modeling transitions. Use the best of both worlds!

3. Flat, Round, Filbert, Fan – Why Shape Isn’t Just Personal Preference

Brush shape isn't just a vibe—it’s geometry.

Flats give you sharp edges and big blocking power.
Rounds are great for lines and precision.
Filberts combine both: they’re the workhorse of most classical painters.
Fans? Not just for blending skies—they can soften transitions in a subtle, controlled way, they also remove unwanted bristle texture.

QUICK TIP : Do a small test sample on your palette before applying it on your canvas.

The shape of your brush influences the mark it leaves—and in classical painting, every mark contributes to form.

▶️ TRY THIS: Visualize the area you want to paint and ask yourself what size and shape fits the best to accomplish the brush function that you desire.

4. Control Through the Tip – Spring, Load, and Paint Release

Here’s a secret classical painters knew: your brush’s behavior depends on three things—its spring (how it bends), its load (how much paint it holds), and its release (how easily it lets go of the paint).

Older brushes were hand-shaped and trained in a certain direction, giving artists insane control. That’s why you’ll see so many precise edges and confident strokes in old master works.

Today? Most brushes are machine-made. They’re good—but not magical. You have to test and break them in a little.

There is no such thing as a perfect brush, just a perfect tool for a certain job!

Final Thought:

Classical painters treated brushes like tools of expression, not just utensils for moving paint. When you choose the right one with intention, your painting suddenly starts talking back to you.