The Pencil Tool is used to draw a single pixel at a time. Dragging the Pencil Tool creates a one pixel wide line.
Using the Pencil Tool with the
It can be helpful to enable the when using the Pencil Tool. The is available at a zoom factor above 200% and shows the outline of individual pixels, making per-pixel editing easier.
The Pencil Tool can be applied using a blend mode selected from the
In the following example, the Pencil Tool was used to draw the bottom and right edges of an icon:
Original Image (with Pixel Grid enabled)
After using the Pencil Tool to extend the bottom and right sides of the icon.