Subtractive methods remove <answer>copper</answer> from an entirely <answer>copper</answer>-coated board to leave only the desired <answer>copper</answer> pattern. In additive methods the pattern is electroplated onto a bare substrate using a complex process. The advantage of the additive method is that less material is needed and less waste is produced. In the full additive process the bare laminate is covered with a photosensitive film which is imaged (exposed to light through a mask and then developed which removes the unexposed film). The exposed areas are sensitized in a chemical bath, usually containing palladium and similar to that used for through hole plating which makes the exposed area capable of bonding metal ions. The laminate is then plated with <answer>copper</answer> in the sensitized areas. When the mask is stripped, the PCB is finished.
In subtractive methods, what metal covers the board and is then partially removed?
copper