Post Tower, Bonn, Germany

June 23, 2004

Architect: Helmut Jahn of Murphy/Jahn
Lighting Artist: Yann Kersalé
Lighting Designer: Michael F. Rohde

The Post Tower in Bonn, built and owned by the Deutsche Post AG and completed in the winter of 2003, is a striking feature of the Bonn skyline. Designed by architectural firm Murphy/Jahn, Inc., the building is an example of a beneficial collaborative effort between client, architect and lighting designer. Throughout the project, Architect Helmut Jahn worked closely with Berlin-based lighting design firm L-Plan and French light artist Yann Kersalé. The result is an architectural success story in which lighting design plays both leading and supporting roles.

Rebranding with color
An integral part of the architectural design concept includes a color changing sequence on over 55,000 square meters of façade. The lighting scheme, created by Michael F. Rohde of L-Plan in accordance with light artist Yann Kersalé, is more than a corporate identity symbol for Deutsche Post AG. It has helped to rebrand the postal service into a dynamic, communications company that brings it eye to eye with the 21st century.

Whereas art is usually applied to architecture as an afterthought, with Post Tower it was an integral part from the start of the project with transparency a key idea behind the design. The main objective of the architect and the client was to underline the light art and the architectural lighting design as integral parts of the architectural design, the result being that Michael F. Rohde and Yann Kersalé were involved in the design process as equal partners from the outset of the project in 1999.

Architect Helmut Jahn wanted the light art, lighting design and architecture, both interior and exterior, to come across as one coordinated entity. It went without saying that a contemporary building of this caliber would include state-of-the-art lighting. Yann Kersalé’s task as a light artist was to pinpoint striking details on the Post Tower. He was most taken with the double-glazed skin of the building, which he chose to work on to design the exterior image of the façade.

Exterior illumination adds substance, aesthetics
The new administration building is 162.5 meters high and encompasses two semi-ellipses set against each other in slightly shifted positions - the entire outer glazed skin a curtain facade with 30 centimeters separating it from the building. Between the two sections is an atrium, which is spanned by a sky garden every ninth floor. It is in this cavity that Martin Architectural color-changing luminaries have been placed.

The intention was to lend the layered transparency of the glass architecture substance, coherence and an enhanced aesthetic sense at night. The Tower is backlit from the inside using Exterior 200 and Exterior 600 luminaires, ripples of warm to cool white and other colors highlighting the façade in a lighting scenario that runs from dusk to sunrise. The dynamic changes in color reveal the double outer skin phenomenon. The architectural volume is enhanced through the interplay of light, transparency and reflection - a completely new dimension for an office building.

Designed with neon points of light that illuminate in a red, blue and yellow sequence, a powerful color changer was needed for the glowing aspect, something neon couldn’t do. Primarily chosen for their power, the Exterior 600s follow in step using the same color temperature to match the neon color perfectly with crisp white projection matching the inside of the building.

Some 84 Exterior 600 and 28 Exterior 200 are built into the double layer façade. The north and south sides of the building have identical fixture placements in six different areas; five of those areas contain Exterior 600s with Exterior 200s positioned at the top of the building. The luminaires are positioned to illuminate the inside structure and window shades. Also, the steel supports that hold and stabilize the glazing in the Penthouse section of the building are accentuated in light, marking the top of the tower and rendering it visible from a distance.

“Architectural lighting has to be flamboyant instead of being flagrant,” quotes Michael F. Rohde who has coined the term ‘urban scenography’ for the dynamic lighting of Post Tower.