Lumenpulse’s Strasbourg Cathedral Project Wins Darc Award

Nov 12, 2017

STRUCTURES: Best Exterior Lighting Scheme – High Budget

The appearance of one of Europe’s most important cathedrals has been transformed with an extraordinary new lighting design from Lumenpulse that uses 400 luminaires. The project recently won an international Darc award. Considered one of the greatest masterpieces of gothic architecture, the iconic Strasbourg Cathedral revels in newfound splendour. The precise and sensitive work of light and shadow creates a highly balanced, poetic ambiance that highlights and embraces shadows.

One of the greatest challenges was to sustain a global and uniform quality of light, and the creation/respect of shadows in the centre of the city. Six hundred LED projectors create warm accent lighting and highlights, which contrast beautifully with the cast and modelled shadows, and result in an overall glow and a peaceful illumination. The ambient lighting effect is achieved using concealed light sources (2700K, 2SDCM), which allow the deep colours of the sandstone and the intricate layers of masonry to be revealed. Focal glow and highlights enhance the numerous architectural details and plentiful sculptures using Dynamic-White luminaires on the building to produce two lighting scenes that play out during the night.

The “Sandstone” is the keyframe of the project. Mostly striped brown and yellow, the stone include a deep and rich gradient of red and purple (corresponding to the R8 – R9 CRI, the weakness colour rendering in diodes quality). Lumenpulse measured and selected a colour temperature of 2700K, dominant length wave (582nm), and chromatic distortion to ensure the quality of light.

The firm worked on splitting and positioning the flood sources for regular modelled and cast shadows, and emphasised the impressive elevation (142m). The consistent quality despite all the different sizes and shapes of floodlights was another challenge for the project. To protect the building (about 14 km of cables and 400 light-sources are installed on the building), all the installation is made without any holes drilled into the stone, only the stone joints. Clamping sleeves, collars, and fixture corsets were created on demand and adapted as needed, projectors were painted onsite to match the colour of stone. Everything can be removed without damage to the building.

The initial terms of references, asked for a “highly qualitative light, revealing the iconic and magnificent architecture of one of finest examples of late Gothic, respectful of its millennial story, and its sacred meaning. Lumenpulse chose to create a precise and balanced illumination, between shadow and light. They combined global ambient lighting with a fixed 2700K to emphasize the volume (in a low lux level, with strong requirement on CRI). The focal glow and highlights enhancing the architecture, intricate layers of masonry, and sculptures come from dynamic white luminaries. The soft gradient of subtle tints allowed Lumenpulse to create two different fixed night-time effects (warmer in the recesses of the building; cooler in the elevation).
No luminaires (except recessed ingrounds) are visible from the external part of cathedral, resulting in a balanced, quiet, “chiselled light” and a magnificent poetic glow of the building.

The primary lighting suppliers included Lumenpulse, Louss, Insta, Radiant, and WE-EF.

About the Darc awards

Darc is an international magazine focused on decorative and design lighting in architecture for the specification and contract markets. Anyone can enter the competition: lighting designers, architects, interior designers or manufacturers. Once the shortlist has been chosen by an international jury of independent architectural lighting designers, each of the 1,400+ lighting design firms and their designers in Darc’s international database are invited to vote on their favourite projects.