Understanding pressure sensitivity
Pressure sensitivity lets you control line attributes that can be made to change as a result of pressure applied to a pressure-sensitive device. The most commonly encountered attribute affected is stroke width, i.e. the harder you press, the thicker the line; the softer, the thinner it becomes. For brush tools, other attributes such as opacity can respond to pressure just like stroke width; you can even combine both stroke width and opacity response in combination.
Techniques that make use of pressure sensitivity include pencil drawing and sketching, as well as vector/raster painting.
Pressure-sensitive devices
To take advantage of natural pressure sensitivity, investment in a pressure-sensitive device to accompany your desktop or iPad device is needed. This would be a standalone device that’s made up of a graphics tablet and an input device such as a stylus (i.e., a touch-sensitive pen that you draw with). iPad devices exclusively make use of a dedicated pressure-sensitive Apple Pencil, purchased separately.
Desktop
- Wacom pen tablets (standalone)
- Huion and most other popular drawing tablet devices (standalone)
- Microsoft Surface devices with Surface Pen
iPad
- Apple Pencil (all models)
Using controllers
Controllers decide whether design tools should respond to pen pressure or to mouse velocity (movement). The latter is used if a pressure-sensitive device is not available to the user. If such a device is operational, apps will automatically detect it so you should be ready to start drawing or painting.
Other controllers may be available to raster brush tools and respond to the angle, tilt or wheel of the pen (stylus); others respond to total stroke length or offer either rotation and/or random scattering of brush nozzles.
Some users prefer to switch the tool’s controller off and instead form their own custom pressure profile that can be reused once the profile is created. In doing so, very similar profiles can be reproduced easily and then fine-tuned if needed.
Pressure profiles
A pressure profile represents the stroke along its length and is visualised in an in-app Pressure chart, which shows circular pressure points arranged along a curve. These pressure points are laid down automatically when using a pressure-sensitive device, but they can be edited afterwards or drawn from scratch by forming the graph’s curve.
Editing pressure profiles using a Pressure chart
The chart is edited (or created from scratch) by moving any selected pressure point around the chart. The higher the pressure point on the chart, the more pressure is applied at the point, giving a thicker stroke width. Moving a point left or right shifts the point where pressure is applied along the stroke. New nodes can be added by clicking/tapping anywhere on the curve.
Editing pressure profiles on the page
In Affinity Designer, the stroke width at any pressure point can be increased or decreased directly on the stroke by using the Stroke Width Tool, independently of the Pressure chart. By doing this, you can:
- Introduce subtle variations at any pressure point
- Edit the stroke in-situ rather than via the Pressure chart
- Easily edit complex, longer strokes without having to use the more confined chart
- Make edits that are more in context with the surrounding design
- Save edited profiles back to the Pressure chart for reuse
This video walks you through how to use the Stroke Width Tool to intuitively alter the pressure profile of vector curves on your designs.
Now you understand the basics of pressure sensitivity, why not give the Pressure chart and new Stroke Width Tool a test-drive in Affinity Designer?