Paint Brush Tool
The Paint Brush Tool is most often used for freehand painting and sketching. The Brush may be used either by quickly clicking and releasing one of the mouse buttons, or by dragging the mouse to produce a painted stoke. The left mouse button will paint with the color on the left side of PixelNEO's Color Box. The right mouse button will paint with the color on the right side of the Color Box. The size, shape and edge (softness) of the brush can be modified using the controls on the Option Panel.
You can draw straight lines using the Paint Brush by holding down the Alt key prior to clicking one of the mouse buttons. Drag the cursor to the point where the line should end before releasing the mouse button and the Alt key. A straight line connecting these two points will be drawn using the current brush settings.
When using the Paint Brush for precise pixel level editing (especially in zoom mode), make sure that you set the Size and Edge controls on the Option Panel to their lowest settings (one) or use the Pencil Tool instead.
When editing 24-bit or 32-bit 16 million color pictures, the opacity of the brush's pigment can be adjusted using the Color Palette's Alpha Slider . The Alpha Slider controls how the selected color and the picture's existing background are mixed. The lower the alpha value, the more of the background will show through.
You should avoid setting the alpha value to zero since that will make the pigment completely transparent which will look like you have no paint on your brush.