Dynamic white light for the Santa Croce facade

Social Innovation Through Lighting. Light has recently turned the facade of the Basilica di Santa Croce in Florence into a bright and pulsating centre of attraction for the F-Light (Firenze Light) Festival, which took place between December 8th 2016 and January 8th 2017. The concept, developed by the Microscape studio, was to animate the Basilica's facade with a dynamic lighting system that plays with intensity and colour temperature, while focusing solely on tones of white. The studio specifically designed a pulsating display on the church's front to express the exchange of energy between the church (which houses the tombs and commemorative monuments of a number of great Italians) and the city and its citizens. iGuzzini worked together with the Microscape studio to identify the best technology to implement this concept. The Microscape project includes the statue of Dante and the church's facade, both of which are lit in a directly frontal way in order to create a distinctive effect with two backgrounds on which the light is alternately focused.

For the first period, up until December the 7th 2016, a static scenario was created with a colour temperature of 4000 K on both the facade and the statue and with floodlights dimmed by 70%. From 8th December until the end of January a light show is being staged, which includes a preparatory period between 5.30 and 6pm. During this half hour the scenario on the facade and the Dante monument is stabilised with a colour temperature of 4000 K and the floodlights operate at 100%. From 6pm to midnight, the light show is displayed, and then from midnight to dawn there is a return to the static scenario.
At 6pm both the facade and statue are darkened. Then a warm light at 3000 K is projected onto the Dante statue, which according to the Microscape concept becomes both narrator and spectator of the light that gradually moves up the facade. The strip of the basilica with the portals is lit first by a 3000 K light, which then rises to the next level and then up to the gables in the facade's third strip and finally to the pinnacle of the structure. At this point the whole facade is lit up, and the lighting on Dante's statue is slowly lowered until the floodlights are operating at only 30% of their power. This is the signal for the entire facade illumination to begin to pulsate. The colour temperature changes from 3000 K to 4000 K and back again in 40-second cycles. Then the pulsating light effect terminates with the entire facade shifting to a temperature of 4000 K and the floodlights dimmed to 25%. At this point the light intensity is varied to focus on the central rose window in 30-second cycles. The light show then terminates in two different stages. First, the lights come on at 100% with a differentiation between 4000 K on the facade and 3000 K on the Dante monument. Then the lights turn off completely and return to 4000 K on both the statue and facade for 5 minutes, after which the entire dynamic light show begins again.

The technical solution adopted consists of 22 MaxiWoody Compact Tunable White floodlights, installed at a height of approximately 12 metres on the pole-tops of two classic luminaires already installed in the square and located 40 metres away from the facade.The floodlights are fitted with 14° spot optics, so they are highly concentrated and directional flaps have been used to further reduce the remote risk of glare. The whole system is managed by a DMX control system. This new solution allows energy consumption to be reduced by about 68 %, while maintaining the same 25 lux lighting levels. Thanks to this project the reliefs on the facade also acquire a greater sense of depth, but above all, it has established a real relationship between the square and the facade, which no longer acts as a separating wall but as a means of communication between the church's interior and the city outside.