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Light and shadow are as essential to architecture as form and
material. It is not simply a question of choosing the suitable
lighting conditions in order to facilitate specific activities, but
also and primarily of the structural, dynamic and atmospheric
role of light. Light always operates in interplay with shadow,
and is perceived as the complement and counterpart of dark-
ness. In architecture, then, it is simultaneously a question of
the appropriate handling of > darkness and of its relation-
ship to light. Light in architecture fulfils a number of tasks:
it allows solid elements to appear three-dimensional, and
shapes the character of spaces through types of openings (1).
Brightness and darkness are decisive resources for articulat-
ing space, as well as for guiding movement through spaces
(2). The character and treatment of light in connection with
materiality is particularly crucial for generating atmospheric
mood (3).- The plasticity of architectural forms and three-di-
mensional elements becomes graspable only when they are
modelled through the distribution of light and shadow. De-
pending upon the three-dimensional shaping of forms and
the incidence of light, the variation in distribution of light is
readable along edges, changes of direction, and curvatures.
Depressions, cavities, joints and surface reliefs become visible
in lateral lighting, while forms remain flat when lit frontally.
In changing daylight, which grazes over surfaces (> surface),
whether uniformly or in streaks and spots, forms are enli-
vened by the changing position of the sun and the shifting or
variable illumination caused by clouds, weather conditions,
and changing vegetation. Their inherently dull masses are
transformed by increasing and decreasing degrees of lightness
and darkness, which wander across their surfaces, oscillating
or flickering.
The principal role is played by natural light. ‘A space can
never reach its place in architecture without natural light’,
claimed Louis I. Kahn. Only daylight can generate dynamics
of movement, changing colour, and fluctuating intensity. It is
Light