Page 35 - Between light and shade

Light, transparency and reflection

rance of the stone when wet, resulting from its
porosity, disappeared thanks to the water-tight-
ness of the glass. Albert Frère was convinced. All
I needed to do was find the required quantity
of glass! At the time, this crystal clear glass was
produced only at the end of life of the refractory
cladding that lines the interiors of furnaces; it is
rare and, therefore, highly sought-after. Fortuna-
tely, I was able to secure the necessary supplies by
picking up the stock intended for maintenance of
the grande bibliothèque de France, in Paris. This
was not quite enough and some quantities from
another source needed to be used, which a close
observer would notice. The same glass is used for
the windows, in an attempt, without a great deal
of success, to mitigate the unpleasant effects of
energy coatings 17.

Compelled by demand, all the major glassma-
kers set about producing almost “crystal-clear”
float glass 18, which is also of benefit to the solar
panel industry. Therefore, we now once more
have crystal-clear glass that respects the colour
of natural light, to the extent that thin coatings
have not been applied to the double-glazed panes.

17 What is more, once fitted with effective double-glazed panes,
at the time, the building was exemplary in terms of energy
efficiency. Nevertheless, it is possible, twenty two years later,
to improve its performance in an attempt to come close to zero
consumption.

18 “Clearvision” from AGC (the most crystal-clear), “Ultra Clear”
from Guardian and “Cristal” from Saint Gobain.
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