185Changes between light and shadow serve to articulate and
distinguish parts of a house and effect the internal zoning of
activity areas. Formed by fields or cones of light, whether the
globe of a lamp, or the zone where wall and floor are illu-
minated by the sun, islands of light are set off in relation to
the surrounding darker space. These become areas of either
retreat or conviviality, and are defined as spatial units with-
out the need for additional boundaries. Or they demarcate
settings where exceptional events are enacted on illuminated
‘stages’. Uniformly and neutrally illuminated spaces, by con-
trast, lend themselves less to differentiated behaviour, and
may even tire by offering too little stimulation. When light
drives darkness from every corner, objects lose their substance
and plasticity, and the room its depth. The leeway for expan-
sion of > personal space also seems to become flattened out.
Spatial rhythms feed on lighting contrasts, as Louis I.
Kahn pointed out: ‘A column and a column brings light be-
tween them. To make a column which grows out of the wall
and which makes its own rhythm of no-light, light, no-light,
light: that is the marvel of the artist.’ (Büttiker 1993, 18)
Likewise, the changing lighting conditions in a > sequence
of rooms lead from one room to the next. In relation to such
sequential passage, however, dramatically deployed contrasts
of light and dark require adjustment. When we enter a dark
room after standing in blinding sunlight, for example, our
mental state changes abruptly while we grow accustomed to
the reduced illumination. Such contrasts can be moderated
by means of > intermediate spaces that are kept in half-light.
Gradual transitions mediate between the intimacy of interiors
and the public character of the outside. Humans are photo-
tropic animals; we tend to move towards light. We can be
led around a corner, lured towards a goal: a bright room at
the end of a dark corridor seems like an important, illumi-
nated scene. Every designed space has its own form of light-
ing, through which it is endowed with a specific gesture.
Rooms are centred or oriented by means of light, and acquire