Mastering Brush Size in Adobe Illustrator: The Designer‘s Guide

As a designer, illustrator, or digital artist, Adobe Illustrator is likely one of your most-used tools for creating vector graphics. The versatility of Illustrator‘s brushes allows you to produce a wide range of artistic styles and visual effects. However, the default brush sizes won‘t always match your creative vision.

Learning how to quickly change and fine-tune your brush size is a fundamental skill that will level up your Illustrator game. With the right sizing, you can add detail and refinement, create bold and expressive strokes, and speed up your overall workflow.

In this comprehensive guide, I‘ll share multiple methods for resizing brushes in Adobe Illustrator across different devices. Plus, I‘ll provide expert tips to help you master brush sizing for your designs. Let‘s jump in!

Why Brush Size Matters

As you probably know, Illustrator offers a variety of brush types including Calligraphic, Scatter, Art, Pattern, and Bristle. Each one can produce diverse results based on its settings, especially size. For example:

• A large Calligraphic brush can create thick, bold lines for typographic designs or rough illustrations
• A tiny Scatter brush adds intricate textures and details
• Resizing Pattern brushes affects the scale of the repeating pattern along a path
• Art brushes may need resizing to avoid unwanted distortion

The ability to quickly resize brushes prevents interruptions to your creative flow. You can adjust on the fly to get the look you want instead of settling for preset sizes. Changing brush size also lets you add variety and hierarchy to your designs.

Additionally, some brushes like Calligraphic are pressure-sensitive. Customizing the size helps optimize their behavior when used with a graphics tablet. We‘ll look at more benefits of resizing brushes later on.

Now that we understand the importance of brush size, let‘s look at the different methods to change it. I‘ll start with the quickest way – keyboard shortcuts.

Resize Brushes with Keyboard Shortcuts

If you want to change your brush size without diverging from your artboard, keyboard shortcuts are the way to go. With Illustrator‘s default settings, the shortcuts are:

• Press the [ key to decrease brush size
• Press the ] key to increase brush size

These shortcuts work for any of Illustrator‘s brush tools, whether you have the Paintbrush, Blob Brush, Eraser, or Pencil tool active. Each press incrementally adjusts the brush size by 1 pt.

To resize in larger increments, add the Shift key:

• Press Shift + [ to decrease brush size by 10 pts
• Press Shift + ] to increase brush size by 10 pts

Try it yourself – select a brush tool and press [ or ] a few times. You‘ll see the brush preview in the toolbar updating accordingly. Open the Brushes panel (Window > Brushes) and the size change will be reflected there too.

This shortcut method is ideal when you need to make quick size tweaks while drawing or editing. However, there are times you may need more control over your brush settings. That‘s where the Brushes panel comes in handy.

Customize Brush Size in the Brushes Panel

For full control over your brush size and settings, open the Brushes panel by going to Window > Brushes or pressing F5. Here you can access all your brush libraries and edit their options.

To change a brush‘s size:

1. Select the brush in the Brushes panel
2. Click the Options button at the bottom
3. In the Brush Options dialog, adjust the Size value
4. Click OK to save

The Size value represents the brush diameter in points. You can enter a specific number or use the slider to interactively preview different sizes. The available size range depends on the type of brush:

• Calligraphic brushes: 0.1 to 1000 pts
• Scatter brushes: 1 to 1000% (correlates with stroke weight)
• Art brushes: 1 to 1000% (scales artwork)
• Bristle brushes: 1 to 10 mm

In the Brush Options, you can also choose how the brush size responds to your stroke. For example, Calligraphic brushes have pressure, tilt, and stylus wheel dynamics that affect size based on your tablet input.

The Fixed option keeps the size consistent regardless of your stroke. You‘ll find additional settings that influence appearance, like Roundness, Angle, Bristle density/length, and more depending on the brush type.

Once you‘ve dialed in your size and settings, click OK to apply them. The Brushes panel saves your changes so you can reuse the customized brush anytime. We‘ll look at how to save size-adjusted brushes as presets later on.

Resize Brushes in the Properties Panel

The Properties panel is another convenient place to change brush size, along with other stroke settings. With your brush tool active, open the Properties panel by going to Window > Properties.

Under Stroke, you‘ll see a Weight (W:) field where you can enter the desired size in points. Press Enter/Return and your brush size will update instantly. You can also click the dropdown arrow for predefined weights.

Note that changing brush size here actually adjusts the stroke weight, which isn‘t exactly the same as resizing the brush tip (more on that later). However, the two are closely related and this method works well for quick resizing.

The Properties panel also lets you change the Stroke Cap, Join, Align, and Profile for your brush. These options, combined with size, give you a lot of control over the final appearance of your strokes.

Resize Multiple Brush Strokes

So far we‘ve looked at changing brush size before or during drawing. But what if you want to resize strokes after the fact? Illustrator makes it easy to select multiple paths and change their stroke weight simultaneously.

First, use the Selection tool (V) to select the paths you want to resize. You can also use Select > All to grab everything on the artboard. With your paths selected, go to the Properties panel and change the Weight value under Stroke.

All selected paths will update to the new stroke weight, regardless of their original brushes or sizes. This method is handy for globally resizing multiple strokes to make them consistent.

Brush Size vs Stroke Weight

You may have noticed that changing brush size doesn‘t always match the stroke weight (the W: value in Properties). What gives? The short explanation is that brush size represents the tip diameter, while stroke weight is the thickness of the resulting path.

Depending on the brush Angle, Roundness, and other dynamics, a 10 pt Calligraphic brush may actually produce a 15 pt stroke. That‘s because the brush "tip" is at an angle, so the stroke weight appears thicker.

In most cases, this distinction won‘t have a huge impact. Just be aware that brush size and stroke weight aren‘t always 1:1. When editing your paths, pay attention to the stroke weight if you need precise control over line thickness.

Proportional vs Non-Proportional Resizing

By default, changing a brush‘s size keeps its proportions consistent. That means a Calligraphic brush with 132% Roundness will maintain that aspect ratio whether the size is 5 pts or 50 pts.

However, there may be times you want to resize non-proportionally. This can be useful for distorting the brush tip or creating perspective effects. To do a non-proportional resize:

1. Select the brush in the Brushes panel
2. Choose Options and open the Brush Options dialog
3. Uncheck "Proportional" under Size
4. Adjust the Diameter (for Calligraphic) or Size (for other brushes)
5. Click OK

Now the brush will resize without constraining proportions, letting you stretch or squeeze it in unique ways. Keep in mind that non-proportional resizing only works with the Diameter/Size setting, not stroke weight.

Saving Custom Brush Sizes

Once you‘ve found the perfect brush size and settings, save it as a preset so you can access it later. This is super helpful for maintaining consistency across designs or speeding up your workflow.

To save a custom brush preset:

1. Customize your brush‘s size and settings in the Brush Options dialog
2. Choose New Brush from the Brushes panel menu
3. Give your brush a descriptive name
4. Choose the brush type (Calligraphic, Scatter, etc.)
5. Click OK

Your custom brush will appear in the Brushes panel, ready to use anytime. You can even share your brush presets with others by saving the library file.

Resizing Brushes on the iPad

If you use Adobe Illustrator on the iPad, the process for resizing brushes is a bit different. Here‘s how to do it:

1. Select the brush tool from the toolbar
2. In the Properties panel, look for Size under Stroke
3. Adjust the size by dragging the slider or tapping the value to enter a number
4. Draw with your resized brush

You can also pinch to resize the brush while drawing. Place two fingers inside the canvas and pinch in or out to interactively change size. This gesture works with Apple Pencil or your fingers.

In the Brushes panel, you can customize your brush‘s settings just like the desktop version. Tap the brush, then choose Options to change its dynamics, shape, bristles, and so on. Save your custom brush by tapping Actions > Add New Brush.

Additional Tips

Here are a few more tips to help you master brush resizing in Illustrator:

• Use a graphics tablet for pressure-sensitive resizing with the Apple Pencil, Wacom pen, or other stylus
• Assign custom keyboard shortcuts for brush sizes you use frequently (Edit > Keyboard Shortcuts)
• Experiment with different brush types and settings to create unique resizing effects
• Check "Scale Proportionately" in Preferences > General to maintain brush size when scaling objects
• Use the Width tool to vary stroke weight along a path after drawing

Wrapping Up

Changing brush size is a core skill for working efficiently and expressively in Adobe Illustrator. I hope this guide has shown you the power and flexibility you have for resizing brushes.

To recap, the main methods are:

• Keyboard shortcuts [ and ] for quick resizing
• Brush Options dialog for full control over size and settings
• Properties panel to change stroke weight
• Brushes panel to save custom sizes
• Touch gestures and Properties panel on the iPad

The key is to experiment with these different techniques to find what fits your workflow best. Don‘t be afraid to customize brush sizes and settings to match your creative vision. With practice, you‘ll be able to resize on the fly and take your designs to the next level.