Pick a brush tool, pick a colour, and drag on the canvas. All brush tools share the same modifiers:
| Modifier | Effect |
|---|---|
| Shift | Draw a straight line from the previous point. |
| Option | Draw with the secondary colour. |
| Command | Erase while held. |
| Control | Pick up the colour under the cursor. |
This means you always have three colours under your fingers at once: a plain stroke paints the primary colour, Option paints the secondary, and Command paints the eraser colour—transparency unless you've set the eraser to a colour. Switch between all three mid-tool, without a trip back to the palette. Dithering goes one further and mixes primary and secondary within the same stroke.
Resize the nib with [ and ] (1–16 pixels). Each tool remembers its own size (Line / Rectangle / Oval share one stroke weight), so a large Pencil and a 1-pixel Eraser stay independent when you switch. See Use brushes and dithering in Dottie on Mac.
The Pencil N is aware of what’s under the cursor. Click an empty pixel and it draws with the primary colour; click a pixel that already has that colour and it erases instead. This makes the Pencil ideal for toggling single pixels on and off. Holding Option inverts the logic and draws with the secondary colour.
If you’d rather a tool that always paints, use the Pen P.
The Airbrush A sprays a random scatter of pixels, densest at the centre of the brush and feathered at the edges. Keep the button held and it continues to spray, building up density even while the cursor is still.
The Smudge tool S captures the pixels under the brush and drags them with your stroke. The captured pixels age as they travel, breaking up through dither patterns until they fade out—and the brush picks up new colours it passes over, blending them into the smear.
The Eraser E paints with the eraser colour—usually transparency, but you can mark any palette colour as the eraser. Brush size and shape apply as with the other tools.
Freehand strokes can leave doubled pixels on tight corners. Choose Tools > Pixel Perfect F to thin strokes as you draw, keeping 1-pixel lines clean.