Saint Peter’s is transformed with LED lighting

A BESPOKE lighting system has transformed Saint Peter’s Basilica in Rome, allowing the art works to be seen in vivid detail for the first time.

A key consideration was to prepare Saint Peter’s for the advent of VHD 4K and UHD 8K television, as many religious services held by Pope Francis are now broadcast live around the world. 

The showpiece all-LED installation – which delivers over 11 million lumens to the church’s interior and cuts operational energy by 90 per cent – follows 18 months of planning by the lighting engineering team at Osram.

More than 780 special luminaires equipped with 100,000 individual LEDs were used in the project.

The 212W luminaires – which deliver 200,000 lumens from 120 LEDs – are based on special fittings originally developed for the relighting of the Sistine Chapel in 2014.

The previous lighting scheme consisted of high-pressure sodium and ‘hundreds’ of 1000W double-ended halogen lamps.

While cutting energy use was important, a strategic aim was to reduce the temperature in the church in a bid to cut the amount of moisture in the air produced by the 27,000 visitors who enter every day.

Specifically, Vatican curators were increasingly worried about the build-up of salt on the frescos and artworks in the 500-year-old building from the sweat of visitors.

The cupola features 111 luminaires and is lit with a ‘cross beaming’ technique in which the fittings are targeted at the opposite side to increase uniformity. A colour temperature of 2700K is used here as it accentuates the gold details.

Another key consideration was to prepare Saint Peter’s for the advent of VHD 4K and UHD 8K television, as many religious services are now broadcast around the world. Specifically, a drive frequency of 225 Hz was used on the luminaire’s control gear to avoid harmonic banding on television images. Additionally, the fittings are distributed across the three different electrical phases to further smooth out any residual flicker.

But what is really attracting attention is the artistic details revealed by the LED lighting. Higher illumination levels combined with a colour rendering of 90 (red is 80) have revealed details ‘unseen by art experts’.

What is really attracting attention is the artistic details revealed by the LED lighting. Higher illumination levels combined with a colour rendering of 90 (red is 80) have revealed details ‘unseen by art experts’.

The engineers are especially proud of the cupola, which was previously lost in the gloom of the previously poorly-maintained traditional lighting. It now features 111 luminaires and is lit with a ‘cross beaming’ technique in which the fittings are targeted at the opposite side to increase uniformity. A colour temperature of 2700K is used here as it accentuates the gold details.

The Dali-controlled luminaires are in turn connected to the Vatican’s KNX building control system.

 The majority of the lights and their bulky control gear sit on a 0.8 metre wide cornice which encircles the interior. Some banks of downlights illuminate the floor to 300 lux during certain services. Otherwise, only the uplighting elements are turned on.

‘The biggest challenge was to hide luminaires’ says Martin Reuter, Osram’s lead engineer on the project. The majority of the lights and their bulky control gear sit on a 0.8 metre wide cornice which encircles the interior.

‘This project demonstrates just how history and high tech can be combined in the best possible way by using the right expertise,’ Osram CEO Olaf Berlien told Lux.

‘This project provides a significant service, both to art lovers and to those who come on pilgrimage to this symbol of Catholicism. We are pleased that a special light has been cast on this important location — thanks to the new illumination,” said Cardinal Giuseppe Bertello, president of the Governorate of the Vatican City State.

The project was a collaboration between the technical services of the Governorate of the Vatican City and Osram.

 

  • The illumination of artworks will be one of the technical sessions at LuxLive 2019, taking place on Wednesday 13 November and Thursday 14 November at London ExCeL. Entry is free - see more information HERE.

 

Pictures: Archivo Fotográfico Fabricca di San Pietro

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