Raising is a term which denotes a technique for creating three-dimensional forms from flat metal sheet by the use of hammers or mallets and formers. Anticlastic raising is a specific technique for making shapes which have two principal curves which move in opposite directions.
The formers used have a dip into which the metal is forced. The cross section is rounded so that as the middle is forced into a curve which continues downwards either side of the stake, the sides are forced upward against the sides of the dip. The workpiece must be held under tension as this process stretches the edges relative to the middle, and so the metal resists. It is this compression along the middle and stretching along the sides which makes the form strong. It can quite easily be twisted side-to-side, but it takes considerable force to deform either curve.