Photoshop

Other Brush options

Noise
Adds additional randomness to individual brush tips. This option is most effective when applied to soft brush tips (brush tips that contain gray values).

Wet Edges
Causes paint to build up along the edges of the brush stroke, creating a watercolor effect.

Airbrush
Applies gradual tones to an image, simulating traditional airbrush techniques. The Airbrush option in the Brushes palette corresponds to the Airbrush option in the options bar.

Smoothing
Produces smoother curves in brush strokes. This option is most effective when you are painting quickly with a stylus; however, it may produce a slight lag time in stroke rendering.

Protect Texture
Applies the same pattern and scale to all brush presets that have a texture. Select this option to simulate a consistent canvas texture when painting with multiple, textured brush tips.