Façade lighting: the main approaches

Flooding a façade with powerful projectors is not enough to make a building look good at night. The key techniques, colour choices and how to avoid disturbing neighbours.

As evening falls, a building either becomes part of the cityscape or disappears into the dark. At the same time, badly set up façade lighting can make a building look flat and cheap, shine into neighbours' windows and dazzle drivers. Good façade lighting starts with reading the architecture: which elements of the building should be visible at night, and which should stay in shadow.

The main techniques

There are several classic methods, and they are often used together:

• Floodlighting: the façade is lit by wide-beam projectors, usually from some distance away. It suits large, plain-surfaced buildings, but it "flattens" relief.
• Grazing: the luminaire is placed very close to the base or top of the wall, so light strikes the surface almost parallel to it. Textures such as stone, brick and decorative render stand out strongly.
• Wall washing: the luminaire is set a little away from the wall and lights the surface softly and evenly; it shows less texture and presents colour and form calmly.
• Accent lighting: narrow-beam spots pick out columns, cornices, the entrance portal, sculptures or a logo.
• Outline and silhouette: the edges of the building are traced with linear fittings, or the building is lit from behind so it reads as a dark silhouette.

For a small office building or shop, a combination of two or three methods is usually enough — for example, highlighting the entrance and showing the main façade with grazing light.

Material and colour temperature

The façade material helps decide the colour of the light. Warm-toned stone, brick and timber look natural and rich under warm light (roughly 2700–3000 K). Under cool light the same stone can look grey and washed out. Concrete, metal, glass and modern white render, by contrast, read more crisply under neutral or slightly cool light. Mixing several different whites on one façade usually looks like a mistake, unless it is a deliberate design decision.

Coloured (RGB) light grabs attention, but it dates quickly and can mask a building's character. On historic buildings or those with serious architecture, white light works better, with colour effects kept for holidays and special events.

Brightness and contrast

How bright a façade needs to be depends on its surroundings. In a brightly lit city centre, more light is needed to make a building stand out; in a dark neighbourhood a little light goes a long way, and an over-bright façade looks crude. Creating contrast is more effective than lighting every surface to the same level: the entrance and key features bright, the rest subdued, some areas left completely dark.

Glass façades are a particular challenge. Glass does not reflect light, it transmits it, so a glazed surface lit from outside is almost invisible. On such buildings the frames, mullions or interior lighting create the night-time appearance.

Neighbours and light pollution

The most criticised aspect of façade lighting is its side effects. With projectors aimed upwards, part of the light passes over the top of the building into the sky, which is both wasted energy and light pollution. Light falling into the bedrooms of neighbouring buildings causes annoyance and complaints. Practical measures include:

• aiming light downwards from above wherever possible;
• choosing a beam narrow or wide enough for the wall, so light stays on the building instead of spilling into the sky;
• using shields and louvres;
• mounting fittings at angles that do not shine into the eyes of passers-by or road users;
• dimming or switching off the lighting on a timer after midnight.

In many cities, façade lighting may require approval from local authorities or building management, so check this before starting the project.

Installation and maintenance

Outdoors, luminaires face rain, dust, sun and temperature swings. A dust- and water-resistant housing, corrosion-resistant fixings and sealed cable connections are essential. For in-ground fittings, make sure water cannot collect and that people walking over them cannot be burned. Position luminaires so that they can be reached for servicing and are as inconspicuous as possible during the day — the façade is the face of the building in daylight too.

After installation, always fine-tune the aiming on site at night: small changes in angle completely change the character of the shadows. Taking a few photos of the result from different distances also makes later adjustments easier.

Zaferoğlu Elektrik makes its Zəfər İşığı LED lamps in Ganja, in a building that once housed a garment factory. Since façade projects need specialised luminaires, whether catalogue products are suitable should be checked together with a specialist.