Page 27 - Between light and shade

Light, transparency and reflection

limits of perceptible colours, which vary from
one individual to another. Architecture can play
a part in this but without the natural reference
point being lost, otherwise our condition could
be distorted.

I produced this light chart with clear skies in
Uccle, Belgium, for each hour and day of the year
on a vertical surface 3 as well as on a horizontal
surface 4.

The resulting two “Lux butterflies” [Fig. 3 and
4] are instructive and an opportunity for reflec-
tion and contemplation. They guide my thoughts
from the first sketch for any project.

orientation And latitude
At a given latitude, the sizes and proportions of
openings depend on their orientation and that of
walls, facades and roofs, as well as environmental
barriers to the sun’s rays. On this subject, it is
essential to remember that the situation differs

3 Facing North, North-East, East, South-East, South, South-
West, West, North-West.
4 It is to Robert Dogniaux that we owe the systematic measure-

ment of these values, since 1954. Institut royal météorologique
de Belgique, Publications série B, nº 12, Ensoleillement et orien-
tation en Belgique. V. Etude de l’éclairement lumineux naturel
(Sunlight and orientation in Belgium. V. Study of natural light
illuminance), by R. Dogniaux, 1954. I have tried, thus far in
vain, to obtain these measurements for other latitudes.

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