To say that Berlin is a city with a complex history is an understatement. The past is a reality that Berlin—and Germany—lives with every day, as its citizens reconcile past with the present, fighting to shed the physical and physiological scars of World War II and the Cold War. Now, two decades after reunification, Berlin is re-emerging as an artistic and cultural capital, once again taking its place on the world stage. Contributing to this renewal is the re-opening of the Neues Museum, which occurred Oct. 16, 2009.

The Neues Museum's epic story—its grand design in the mid 1800s; its near-demolition as a result of heavy Allied bombing during World War II; its abandonment and decay during the Cold War; and its recent rebirth—embodies in a most singular fashion the trajectory that city and country have taken in coming to terms with the past and moving toward the future.

The new Neues Museum, as conceived by David Chipperfield Architects in collaboration with conservation architect Julian Harrap, is a project that defies description: part restoration, part renovation, part intervention. It is a work of great complexity, achieving much through addition, and even more through restraint. What has been created is nothing short of a masterpiece.

A lack of funds prevented the East German government from restoring the building, and it was not until reunification in 1989 that the task could be seriously considered. An international competition was held in 1994. Italian architect Giorgio Grassi was chosen as the winner and Chipperfield as the runner-up. But the complex politics surrounding the project—so closely linked with the national identity—stalled the selection process, and a second competition, open to the five finalists from the first go-round, was held in 1997. This time the winning proposal was Chipperfield and Harrap's.

The project took nearly 10 years to complete. Chipperfield and Harrap, along with a long list of consultants, have masterfully stitched old and new together, creating something completely unique while respecting the original architecture. The project rigorously follows UNESCO's 1964 International Charter for the Conservation and Restoration of Monuments and Sites, known as the Venice Charter, which requires a structure that is stable to be maintained. Parts that are not stable need to be replaced with work that is expressed as a clear addition. Over the course of the Neues Museum's rehabilitation, the site became a working laboratory for restoration methods, and many of the techniques employed, such as the infill of crumbled masonry, are completely new.

The Neues Museum is the second of five museums built on an island in the Spree River, which runs through the center of Berlin. Called Museum Island, the complex was conceived by Frederick William IV of Prussia as a “sanctuary for art and science.” The first museum on the site—the Altes Museum (1824–1830)—was designed by the great neo-classicist Karl Friedrich Schinkel. That was followed by the Neues Museum (1843 –1855) designed by Friedrich August Stüler, Schinkel's student and architectural heir. Next to be constructed were Johann Heinrich Strack's Alte Nationalgalerie (1867–1876), and the Bode Museum, designed by Ernst von Ihne and completed in 1904. The last museum to be built as part of the complex was the Pergamon Museum, begun by Alfred Messel in 1910 and completed by Ludwig Hoffman in 1930. In 1999, Museum Island was designated a UNESCO World Heritage site, and the long process of rehabilitating all five museums began.

A LIGHTING DESIGN STRATEGY When David Chipperfield Architects received the Neues Museum commission, the office was relatively unknown outside of the United Kingdom. The project's lighting designer, Berlin-based Kardorff Ingenieure, was also just coming into their own. Despite the daunting prospect of working on such a large and historically significant project, The Neues Museum was a chance for all the team members to further establish themselves.

From the outset, the Kardorff design team, following Chipperfield and Harrap's lead, believed that the building's history should be visible. As lighting designers, the Kardorffs (the husband and wife team of Gabriele and Volker von Kardorff) took their cues from Stüler's design. The museum originally was open only during the day and relied heavily on natural light via large windows and courtyards with glass roofs. “When Stüler designed the Neues Museum he had no means of electric lighting,” Volker von Kardorff explains.

The Kardorff team began by conducting a thorough analysis of the building and by building a 3D model and walkthrough film that would enable them, the architects, and the museum clients to “see” the effects of natural light on the building at different times of the day and year. The 3D model also would aid the designers in determining how to reconstruct the entire northwest and southeast sections of the museum, which had been devastated by wartime bombing and left completely exposed to the elements in the ensuing years.

The daylighting studies led the Kardorffs to develop a series of universal sun-shading and glare-control strategies for use in all of the museum's 50-plus galleries, while still responding to the specific needs of each space and of the artifacts on display. (The museum reunites two collections: Egyptian and Early History.) “We wanted to create a lighting scheme that would complement the daylight entering the museum as well as enhance the readability of the art work,” says Gabriele von Kardorff.

One of the first spaces they considered was the 100-foot-tall Stair Hall. Once an elaborately frescoed, rectangular space with 20-foot-tall windows, the hall had been reduced to a shell. Chipperfield reconstructed the stairs out of polished and sandblasted concrete, outfitted the hall with a new ceiling, and exposed the surviving brick walls to reveal new sections of masonry infill. To complement and balance the daylight from the trio of windows at either end of the space, Kardorff Ingenieure installed electric lighting in the coffers of the oak ceiling, the only available location since the walls were meant to stay free of any kind of fittings. Only the display of several frieze reliefs is permitted. A motorized lift allows access for maintenance and relamping.

Hoping to avoid light scalloping on the exposed brick walls, the Kardorffs worked through 12 light simulations to determine the right layout for the fixtures, and they designed a square luminaire with two to four 35W metal halide lamps and a bronze finish that matches Chipperfield's material palette.

On the windows in the Stair Hall and throughout the museum, dark gray colored shades with a perforation pattern protect the interiors from glare and direct sunlight, reducing light transmittance by 4 percent. Again, elaborate studies taking two years to complete revealed the right balance of color to fabric weave density that would maintain a visual connection with the outside, but modulate the light according to conservation requirements.

SITE SPECIFIC SOLUTIONS In addition to the Stair Hall, two of the museum's other grand spaces are the Greek and Egyptian courtyards. Kardorff Ingenieure's approach to both builds on the original daylighting strategies from Stüler's period and moves them into the 21st century. A clear glass roof encloses the Greek Courtyard, admitting direct sunlight into the space without any shading device. This scenario is permissible given the durability of the art on display—sculptures, statues, bas-reliefs, and a cornice frieze depicting the destruction of Pompeii. To balance the natural light but also enhance the readability of sculptural details, the Kardorffs mounted projectors using 150W metal halide lamps between the two layers of the glass roof. A shutter attached to the luminaires, explains Gabriele von Kardorff, allows important features on the bas reliefs to be highlighted without creating hard shadows and hot spots on the walls.

The lighting designers took a different approach for the Egyptian Courtyard, which houses galleries on three different levels. The Kardorffs still used a double-layer glass system, but here diffuse light illuminates the uppermost gallery, a freestanding platform whose new columns are aligned to the sun. The lighting designers conducted a series of mock-ups at the Pergamon Museum next door to test different types of glass, the spacing between the two layers of glass, and the positioning of spotlights within the glass roof assembly. Ultimately, the Kardorffs selected a diffuse glass with a light transmittance of 71 percent for the visible layer and a clear glass for the second, outer layer. Custom-designed floodlights with 150W halogen lamps positioned 16 inches from the glass add the necessary illumination balance. The floodlights are spaced on four tracks. The fixtures on the two outer tracks are positioned at a 15-degree angle to illuminate objects from the Egyptian collection and fragments of landscape frescoes that remain on the gallery walls of the level below.

The various galleries presented different challenges and therefore afforded different solutions. For example, in the new galleries in the northwest wing, the pre-cast ceiling enabled the lighting designers to fully integrate a custom luminaire with both general and emergency egress lighting features. In the surviving original galleries with domed ceilings, which could not be touched without damaging the remnants of painted surfaces, the best solution wound up being a track system fit in between the columns. Overall the project has 3,000 luminaires and 100 special fittings. “The design of the fittings is technically driven without any decorative attitude,” says Gabriele von Kardorff. “Where luminaries were applied in new ceilings, they are integrated into the structure. In many cases, the fittings comprise other technical devices such as loudspeakers.”

Throughout the galleries, both the general and exhibition lighting responds to the particular conservation issues of the artwork on display. To deal with these disparate conditions in the first floor rooms, the Kardorff team developed an uplight that casts light on the ceiling but not on the sensitive historic murals and other painted surfaces. Three types of light sources are used in the galleries: 35W and 50W tungsten halogen spotlights with 6- and 26-degree beam spreads; QR111 35W and 50W lamps with 4- and 8-degree beam spreads; and 50W to 65W IRC lamps with an 8- to 24-degree beam spread. For general lighting, fluorescent and metal halide sources are used.

In the few instances where exhibit lighting could not be incorporated into the architecture, curators can turn to specially designed cases with fiber optic lighting employing 150W 3000K lamps. All of the lighting choices had to be energy efficient to comply with code. The designers further were limited in what types of lamps they could use in order to maintain a comfortable temperature in the galleries—for people and the art. Overall, considering the energy used to maintain all the building systems, the lighting load could not exceed 20W per square meter.

FINISHING TOUCHES One of the prize possessions of the Neues Museum collection is the famous bust of Nefertiti. According to Gabriele von Kardorff, it was lit very well while being displayed at the Altes Museum, during the Neues Museum renovation. To plan for the lighting in its new home, Gabriele von Kardorff documented the locations and angles of all the luminaires of the Altes Museum installation. The positions of fixtures for the Neues Museum installation had to be perfect. Once again the designers couldn't touch anything on the ceiling, so they developed a track system that rings the gallery and is located in the existing cornice line. To bring the statue to life required five different spotlights: four 50W halogen sources with a 4-degree beam spread—two on the bust's backside, one on its right side, one on the front—and one source directly on the pupil of her eye. Ms. Kardorff tested the layout on a replica until the original was set in place, only two weeks before the official museum opening.

The project was set on an incredible pace. So important was this rehabilitation, the museum opened to the public in March 2009, while still empty of art. The exhibits began arriving in April, and their installation continued until the day before the official opening in October. The Kardorff team worked around the clock in two shifts to focus the lighting as exhibits were installed. Everything had to be perfect, as there would be no chance to go back after the opening and make adjustments. Because the exhibit layout was not fixed until the moment of installation, the designers had to plan for every contingency, creating up to five different scenarios for each lighting situation. Fixture schedule and lamp documentation took on a heightened importance.