This post concludes the simple mouldings by covering both three-quarter mouldings in one go: the convex three-quarter round, and its concave counterpart the three-quarter hollow. As the names suggest, these mouldings are formed from three-quarter arcs, giving two neat groups of arc mouldings as you ‘go around the clock’: the 90° ovolo – 180° torus – 270° three-quarter round convex arcs; and the 90° cavetto – 180° scotia – 270° three-quarter hollow concave arcs.
The three-quarter mouldings produce even darker and sharper shadows than the torus and the scotia. These are dramatic mouldings, and they play a prominent role in generating the undulating, dusky, mysterious atmospheres of gothic architecture. The pendulous three-quarter round seems almost ready to drip from the wall; if too big, it will dominate and unbalance the composition, so is often used as a small bead rather than a larger round. In contrast, the three-quarter hollow looks like like a breaking wave. If used as a ceiling moulding, it acts to detach the ceiling from the walls and give it the appearance of floating in space.
When horizontal, the three-quarter mouldings are generally used above eye height, and they almost always face downwards; if facing upwards, they will fill with water or dirt.
