Pastel is a dry media, softer than chalk, but like chalk it has infinite
brush loading. Applied with the Pastel tool 
, its dry
pigment tends to penetrate the canvas texture proportional to the pressure
at which you apply it. Pastel pigments have a fixed viscosity slightly
less than chalk, meaning the strokes you apply leave some volume on the
canvas as they break from the pigment stick. Pastels
do not have a bristle component to the stroke, instead presenting a flat
or angled surface of the stick. The
stroke edges tend to have a fall-off and break up affected strongly by
the canvas texture.
Pastel is slightly shiny, interacts with itself by smearing slightly, and dirtying the tool head slightly when applied with light pressure. It loads the canvas more than chalk, breaking up more when applied, and this give the appearance of volume to the surface.
Pastel tool options include:
Shape: Choices include Round or Square.
Size: Defines the size of the tool head in pixels. Note that you can also adjust the Size setting via the keyboard.
Thickness: Defines the aspect ratio of the tool head.
Rotation: Defines the angle of head rotation in degrees
Head Tracking: Controls whether the tool head bends around the path of the user’s stroke, or remains at a fixed angle.
Trace check box: When marked, the Pastel tool will select the pigment color by sampling the data below the center of the tool regardless of the layer type. (This feature works much the same way the Clone Brush's Sample Merged tool option works). When you hold down the mouse button to begin the stroke, note that a single sample is performed, and the resulting color is used for the duration of the stroke.
Like other Paint Shop Pro tools, the Pastel tool comes with presets. To use a preset:
In the Tool Options palette, click the Presets button. This displays a list of preset styles.
From the list, choose the desired tool preset.