Anatomy of a Brush
First, realize that a Brush is technically any tool that's linked up with the controls in the Brushes panel. That means that not only is the Brush Tool a brush, but so are all of these:
- Brush Tool
- Pencil Tool (Basically a quick way of choosing a small brush)
- Not the rarely used (read, useless) Color Replacement Tool
- Mixer Brush Tool (Very Cool!)
- Clone Stamp Tool
- Pattern Stamp Tool
- History Brush Tool
- Art History Brush Tool
- Eraser Tool
- Blur Tool
- Sharpen Tool
- Smudge Tool
- Dodge Tool (Lighten and decrease contrast)
- Burn Tool (Darken and increase contrast)
- Sponge Tool (Desaturator)
That's 14 different tools that use the Brush Engine in Photoshop. But for our purposes, let's just consider these 4:
Brush Tool
Mixer Brush Tool
Eraser Tool
Smudge Tool
Reset Brush Settings
First, let's choose the Brush tool from the Toolbar
Next, let's pick a brush, like Soft Round from the Brushes panel
And let's break down the most relevant settings. Many of the settings are irrelevant or useless, but the most important three are:
- Brush Tip Shape
- Shape Dynamics
- Transfer
Brush Tip Shape
Note: You can create your own brush shape by drawing it then selecting
Menu Edit Define Brush Preset...
This controls the shape of the brush. You can even capture a shape from the document window to use as a brush shape (advanced, but maybe we'll cover it later). There are 30 different tip shapes used in the Default Brushes. You can control:
- Default Size
- Overridden by the [ and ] keys and by Control+Option (Mac) Alt+Right Mouse (Win) Drag left/right
- Unlike other properties, Size is not usually set as a part of the brushes properties, so when you return to the brush after using another, it will be the last size it got set to
- Roundness and Angle
- Controls the aspect ratio of the brush tip shape. Can be flipped with the two check boxes.
- Default Hardness
- How soft or hard the edge of the brush tip shape is. 0% is as soft as possible, 100% the hardest
- Override by the { and } keys and by Control+Option (Mac) Alt+Right Mouse (Win) Drag left/right
- Spacing
- The distance between imprints of the brush tip shape, in percent of the tip's size. 1% minimum is as close as they can be set together, 1000% the maximum.
Shape Dynamics
This controls the Size, Angle and Roundness of the brush. Mostly, it's what allows a brush to react to pen stylus pressure
- Size Jitter
- Jitter is an important concept in Photoshop brushes. It's what gives a sense of randomness and
non-computerness
to a given property. In essence, it randomly changes the value of a property. Measured as a percentage of the maximum range (sort of). - Size Control (first Control popup)
- Popup menu to select the control method for the Size of the brush tip shape. You can choose from Off, Fade, Pen Pressure, Pen Tilt, and Stylus Wheel
- Fade: Let's the brush size fade out as the line is drawn out
- Pen Pressure: The most common use for a graphic tablet. The harder you press the stylus, the more the brush size changes.
Most pens have a sensitivity level between 0 and 1023, while some have between 0 and 2047. I don't think it's humanly possible to sense that many levels.
- Pen Tilt: Most tablets can give feedback on the tilted angle of the stylus relative to its surface, from 90° to around 40°. This can be used by Photoshop as a control. Personally, I've never been able to make it useful
- Stylus Wheel: Some tablet styluses have wheels built into them like the scroll wheel on a mouse (on the left). Made to act like a traditional airbrush (on the right).
- Minimum Diameter
- The diameter of the brush when the lightest pen pressure is applied
- Tilt Scale
- Only available if the Control of the Size is set to Pen Tilt
- Angle Jitter and Angle Control
- Usually the Control of the Angle is set to the Pen Tilt control. I've never been able to get the hang of it...
- Roundness Jitter and Roundness Control
- You could use pen pressure for this, but it's mostly useless
Transfer
Contains two important properties, Opacity and Flow. Opacity, as we know, can also be controlled with the Number keys at the top of the keyboard, and is pretty much what it sounds like. You can also think of it as Transparency, but the higher the Opacity value is, the more opaque the brush is.
Flow, on the other hand, is the amount of color the brush lays down as if moves over itself and when the brush isn't lifted off the document. Hard to explain, works best with Airbrush style brushes and a few others... Mostly, it's handy for building up color slowly with multiple passes of the brush.
Opacity set to 50, Flow set to 100%. Notice that the diagonal stroke is a second drop of the brush and you can see the layering of the opacities
Opacity set to 100, Flow set to 5%. This example is one single stroke. Notice that the color builds up and becomes more opaque at the bottom where I've used multiple passes (without lifting) of the brush.
The other Brush Settings (and there are a lot of them) are less important for now.










