Some works gain a certain character due to the effects of weathering. In many of these works the effect of the 'distressed' look is called patina. Bronze sculptures and copper aspects of architecture that are exposed to the elements turn color over time due to oxidation. In some cases the color turns a darker, richer color, as in this sculpture by Antoine-Louis Barye. In others it turns green. The color of this patina is called verdigris. Here is a sculpture by Henry Moore. This color effect is so appealing to some artists that the color is artificially achieved so that it does not take time for it to develop.