The perception of smooth surfaces is supported by the uniform brightness progression. Uniformity on both vertical and horizontal planes results in walls appearing to be flat, making it easier to recognise rectangular spatial structures. The uniformity of the lighting allows the object to be appreciated in its entirety. Wallwashers produce excellent uniformity for this lighting application.
Patterns of light projected onto flat surfaces reveal the curvature. The wavelike progression of light and dark similarly evokes such an impression.
A cylinder can be made to look less round by using a very uniform brightness distribution.
To make a round object appear more three-dimensional, illuminate it from two sides and have a brightness gradient that accentuates the shape.
To reveal the shape of an organic structure, accent lighting is used to emphasise the contours and curvature of the sculpture through the progression of the shadows. The result is that the overall form of the object can be clearly appreciated. By lighting the sculpture alone attention is directed to the amorphous form, and the rectangular support structure recedes into the background. The narrow beam angles of the spotlights avoid the observers from being dazzled as they move around the room ensuring good visual comfort.
Individual curves on sections of the object can be emphasised using spotlights to add striking accents. Recognition of the overall shape is reduced as attention shifts to specific accentuated areas.
The exaggeration of details instantly produces a dramatic effect.
By contrast, the blanket illumination of complex structures presents the object as a whole and reduces the three-dimensional effect. By decreasing contrast of light and shadow on the object, the effect is nowhere near as stimulating as when directed accent lighting is used. It also means that the variations in the shape will not be so easy for the observer to see. Producing this uniform lighting requires some unconventional luminaire positions, such as from the side or on the floor with wide beam angles, in order to avoid these being shadows on the underside. This does mean that the observers themselves will cast shadows on the object when standing in front of it and they are likely to be dazzled by the light.