If no show is on, the light intensity graduates and carries on in an undulation that climbs up to the roof. When all activity stops, the vault goes to sleep. Only the two lines at its base remain lit, similar to embers.
At the end of his night watch, the fireman on duty can set off, the fire on the glasshouse, for a few seconds – an ultimate signal in the city of living opera.
From the fall of night till 3 o’clock in the morning, the Opera reddens in accordance with its activity, the variation of intensity is more or less paced depending on the moment the eye sees it. As it increases progressively, diffused by metallic sun-shade blades, red light then fades out in magenta pink.