Dragging in the image with this tool creates colored strokes similar to what might be created by a paintbrush. The way the paint is applied varies according the options you have selected.
The basic painting procedure is to
1. choose your foreground color by clicking on the foreground square in the toolbox or the Color palette
2. set your options (explained below)
3. select a brush from the pop-up palette in the options bar
4. drag in the image to paint.
Note that you can limit the area that paint can be applied to by making a selection and then painting inside it. Paint will only appear within the selections outline, even if you drag over areas outside of it.
Straight lines can be painted by clicking once in the image where the line should begin, and then Shift-clicking where you would like the line to end.
A shortcut for changing brush sizes while using any of the painting tools is to press the left bracket [ to decrease brush size, and the right bracket ] to move to the next larger brush. Pressing Shift with the bracket keys will increase or decrease brush softness. Shift-right-clicking on your document while using this tool will open the blend modes menu next to your cursor.
If you choose Edit > Fade immediately after using this tool, you can change the opacity and blend mode of the strokes you have just applied.
If you have chosen "brush size" in Display & Cursors preferences, (find at Edit > Preferences > Display & Cursors ), you can toggle to "precise" by pressing Caps Lock. If you have your preference set to "precise", it will toggle to "brush size". A preference of "standard" will go to "precise" when Caps Lock is pressed.
The keyboard shortcut key for the brush tool is the letter B. Toggle between the brush tool and pencil by pressing the Shift key, and the shortcut letter.