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Techniques

GeneralThe purpose o architectural foodlighting is to reveal the beauty o a structure or in somecases add a dimension by showing a structure in a new way. Architectural lighting addsan aesthetic quality to a scene. Points o note are:

Generally a structure will have one or more principal viewing positions.Thereore the lighting should be sympathetic or an observer positioned atthese viewpoints.

The light levels used on a structure should be in harmony with the light levels

o the surrounding area. In darker areas comparatively little light can be usedto good eect, but in areas with a large amount o ambient lighting higherlight levels will be required.

A coherent fow o light across a structure is oten desirable, implying onegeneral aiming orientation or the main foodlights. This direction should notcoincide with the most common viewing direction or the structure as noshadows will then be visible and the scene will appear fat and uninteresting.

Care should be taken when mounting the foodlighting equipment to ensurethat the lighting units do not appear in silhouette against the lit scene, as this

will spoil the overall eect.

Structural detail

The main objective is to highlight signicant eatures o the structure whilst ensuring thestructure still appears as a coherent whole. Points o note are;

Light naturally attracts peoples attention so highlighting specic eatures willhelp an observer read the structure. Care should be taken to only light thosedetails that are required, as too many highlights will destroy the eect andeither makes the structure appear bland and uninteresting or disjointed andincoherent.

Completeness o lighting is an important consideration to ensure a coherentwhole. Care should be taken to avoid a foating appearance, caused by thebase o the structure being under lit, or high level lit detail seemingunconnected due to the upper parts o the structure being insuciently lit.

Shadows can make as useul a contribution to the nal lit eect as doilluminated areas. A good technique is to highlight specic eatures and togive a low-key wash o light to the rest o the structure. Thereore smaller

lighting units are needed to highlight the detail, as well as units with a moregeneral distribution to cover the broader area.

5.10 Urban architectural foodlighting

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Positioning foodlights at a distance rom a structure and thereore giving lightcloser to the horizontal will tend to reduce the visibility o the textures o thematerials used in the construction o the structure. Conversely positioningfoodlights in a close oset position, and thereore giving light closer to thevertical will tend to enhance the visibility o the textures o the materials usedin the construction o the structure.

Daylight has a generally downward bias, orming shadows rom architecturaldetails below the detail itsel. Floodlighting a structure rom above can mimicthis eect, whilst foodlighting rom below will reverse the shadows and canoten give a resh appeal to a structure by giving it an individual day timeand night time appearance. Lighting laterally will enhance any verticaleatures o the structure.

Showing eatures in silhouette may enhance the lit appearance o a structure.Lighting behind eatures such as columns will show the orm o the structureand display the columns in silhouette against the lit structure.

Obtrusive light

The main objective is to maximise the amount o useul light (that is light alling onto thestructure) and minimise waste light that spills light onto the surroundings or upwards intothe sky. Points o note are:

Close o set lighting will reduce waste light by minimising light lost throughscatter in the air, especially in urban areas with lower air quality.

When uplighting a structure the upward light ratio (ULR) is not very useul asan indication o obtrusive light. A more useul measure is the utilisation actor,that is the amount o light actually lighting the structure compared to the totalamount o light produced by the scheme. This gives the percentage useullight, and thereore the percentage waste light. It should be remembered thatany refected light will be in a predominantly upward direction and can givea signicant contribution to obtrusive light. Thereore where possible

uplighting should be used or structures that use low refectance materials intheir construction.

To minimise obtrusive light additional attachments should be used on thefoodlight such as louvres or visors to shape the foodlight beam and help itconorm to the shape o the structure.

Where possible niches and overhangs should be used to contain obtrusivelight.

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Urban architectural foodlighting

Floodlight technology

The main objective is to ensure that the correct technology in terms o lamp, optic and

foodlight body is chosen or the application. Points o note are:The abric o a structure has a colour, or in many cases a mixture o colours.Light sources that are monochromatic or strongly biased towards a smallrange o colours can distort the structure appearance. Thereore, light sourceswith a wide spectrum, (such as metal halide) or with a colour temperature thatblends with the structure materials (such as high-pressure sodium on sandstone)should be used. Colour lters or RGB colour mixing should be used with carebut can be very eective or dramatic eects or seasonal/estive events.

Floodlights have a beam distribution that is mainly relative to the shape o the

refector. A round refector will produce a conical beam useul or long-throwrequirements, typically to pick out a single eature. A rectangular refector willproduce an asymmetrical beam useul or lighting areas rather than small points.

Constraints in mounting position or specic application requirements otenrequire a modied beam distribution. Additional optical components such asreractor glasses that vary the beam shape, or louvres that reduce obtrusivelight are useul in getting the correct result.

Floodlighting set-ups are generally aimed at night to enable ne-tuning o the

nished appearance. However maintenance will be done in daylight, andoten the foodlight will need to be moved to allow access to the lamp, etc.Floodlights with a re-positioning lock system are helpul to ensure the litappearance is maintained over successive maintenance operations.

Key luminaires:

Scheme: Building aadeLuminaire(s) used: Avenue Deco bollard

50W MBF, AvenueDeco 125W MBF at 3mmounting height, EactLED, Mica B 70W HIT-DEand Contrast Pinspot70W Par 30.Road Eav = 7lux

Pavement: Eav

= 15lux away rom the aade,

Eav = 35lux along store aadeSchemes Building acade

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Urban architectural foodlighting

The curved roo is washed with light, making it appear to foatover the building. The structure itsel glows rom the interior lightspilling through the glass acades.

Lighting o glass acades is dicult and it is more usual to letspill light rom the interior light up the building and dene itsnight-time appearance.

The suspension tower and cabling are lit to provide a distinctiveappearance. Narrow beam foodlights are directed along thecables to make then glow, whilst the central tower is washedwith light. The structure seems to foat above the surace o thewater.

The appearance is built up using layers o light. The lowersection o the building has a general wash o light withhighlighting above the central columns. Lighter and darker areasgive depth to the aade. The upper storey mainly comprisesgrand window openings, and these are lit with a white lightto accentuate the detail o the window surrounds. The detailaround the top o the aade (below the roo line) is lit to denethe transition to the roo space, and additional windows within

the roo space are lit, along with chimney work, with a smallamount o spill light showing the roofine.