Overpainting can mean the final layers of paint, over some type of underpainting, in a system of working in layers. It can also mean later paint added by restorers, or an artist or dealer wishing to "improve" or update an old image—a very common practice in the past. The underpainting gives a context in which the paint-strokes of the overpainting become more resonant and powerful. When properly done, overpainting does not need to completely obscure the underpainting. It is precisely the interaction of the two that gives the most interesting effects.