In any city illuminating monuments in a recognised manner brings out traces of the historical past in urban cityscape as well as landscape. Monuments recalling and showing respect for important persons or events are often located on pathways, in public squares and city parks where they form the end point of an axis line or stand in the centre of observation themselves. A determining factor for ensuring that monuments are noticeable from a far distance is the luminance contrast with respect to the surroundings. In a rural or large open area context with a low ambient illumination, low illuminance levels are sufficient for highlighting a building or structure, but a brighter urban environment (along pathways or in public squares) will require a correspondingly brighter emphasis to achieve a comparable contrasting effect.
A fractionally higher illuminance level will often serve for giving significant buildings or monuments an intensive effect from a far distance. However, as the structure is approached, the focus shifts from the overall image to details such as reliefs of engravings or lettering etc. A brightness level that is too intensive would dazzle a viewer and be recognised as annoying. The possibilities for lighting design for monuments range from ultra-fine, uniform illumination to meaningful, temporary lighting concepts for celebratory occasions.
When deciding on the right lighting concept for any monument, the history and usage of the monument play a critical role. Memorials that celebrates a difficult past and serve as a place of historical observation and grief should use a differentiated lighting design to respectfully bring out that history and to offer the individual visitor a better atmosphere for meditation. What definitely must be avoided in such cases is uniform lighting with high illuminance levels and the glares.
Monuments that boldly mark positive events and symbolise national pride (like India Gate in New Delhi, Refer Figure 2) permit a different approach to lighting. Light enables history to be clearly presented also at night and even to be dramatically showcased with special effects on public holidays or special days. Sometimes cultural monuments can serve as the geographical centre or major landmark of the city both day and night and as backdrops for concerts or events, while bringing history back to life. Below given are the few basic fundaments to be adopted while designing lights for monuments.
Respect the History
A respectful behaviour towards history is also reflected in the lighting design; one that places the lighting in the service of the structure or monument rather than putting the lighting centre stage. The India Gate Memorial in New Delhi of India, honouring 70,000 soldiers of British Indian Army who died in the First World War, is noted for its simple lines and impressive lighting design.
The US Air Force Memorial in Arlington, Virginia is much monumental, with its three divergent pillars soaring over 80 metres up into the sky. Designed based on the moisture trails of a formation flight activity, its metallic stainless-steel surface makes the sculpture visible from afar distance (Refer Figure 3). Illumination is provided by narrowly focused beams from precisely aimed projectors. These are equipped with powerful metal halide lamps.
The lower part of this monument is illuminated by projectors located directly on the plinth area of the curved pillars. Uniform lamps simplify maintenance of the installation and ensure the lighting quality remains constant.
Artistically designed objects such as sculptures take on an important role in the pictorial language of monuments for paying tribute to any persons or events. When apply light to shape these monuments during dark, it is not only the light’s angle of incidence that is relevant but also its direction is important. A frontal light, by which the direction of the light is the same as the observer’s viewing direction, will produce a low modelling effect. A shadow will be barely noticeable and the three-dimensional objects will appear flat.
Conversely, a light from the side of the sculpture will produce very strong contrasts between light and shadow with an intensive three-dimensional effect for the viewer. Similarly, an overhead light, whereby the light is incident on the object from directly overhead, greatly highlights the upper surfaces of the object but often causes the sides disappear into the darkness and casts a spotlight circle on the ground.
Backlighting with a light source behind the object casts a long shadow towards the observer, leaving the object as a dark profile with just a thin border of light outlining the upper contours. Floor lighting illuminates sculptures from underneath and often gives an uncommon effect because the direction of light is the opposite to that of daylight. These effects not only hold true for sculptures or monuments but are also relevant for object lighting in general way. Refer Figure 4 for a picture showcasing the perfect luminance contrast to surroundings along a walkway to perceive the queue of sculptures from a distance.
Monument as a Backdrop
Cultural monuments provide spots with a unique atmosphere for festivals, events or concerts. Often situated within landscapes of particular area, these structures can be used as a stage set for concerts, events or performances, lending them a surprising backdrop or even embedding them in the historical contexts. In such cases, the lighting can express the theme of the event. Refer Figure 5 for picture showcasing the live concert done by famous keyboardist and music producer “Yanni” in 1997 using backdrop of one of the seven World’s Wonder “Taj Mahal” monument of India.
Lighting control systems and luminaires are capable of different colours enable great flexibility for setting up light scenes and sequences. A perfect lighting control system can control the flowing transitions between the different dramatic light scenes as per the event, festival or concert.
The key tool for lighting sculptures or monuments are projectors and floodlights, and luminaires for open area and walkway lighting. There are only two principles important for mounting the luminaires, giving rise to two different aesthetics; “integrated and additive lighting”.
With integrated lighting, such as in-ground or in-wall luminaires, it is the landscape and the architecture that comes to the emphasis; the focus is on the light not the luminaires. Conversely, with additive lighting, such as surface-mounted luminaires, the luminaires act as an architectural feature in their own right. In the case of existing monuments or sculptures, mostly the utilisation of integrated lighting is important in accordance with the listed building regulations or laws (if any).
The options for the lighting technology to be adopted are barely influenced by the decision for an integrated or additive concept. The main criterion for choosing the luminaire includes the visual comfort, the light distribution, the options for accessories and the choice of various types of lamps. The architect or lighting designer can obtain good visual comfort by selecting luminaires that reduce glare, due to their cut-off angle, and that prevent a direct view of the lamp as far as possible. Refer Figure 6 for the image showcasing the Statue of Liberty of United States, enlightened with a good visual comfort during night time.
It is vitally important that luminaires in the outdoor area also satisfy the safety requirements and this is attested by the presence of a mark of compliance with the related building rules and regulations.
For economical lighting in outdoor areas, generally three types of lamps are used. High-pressure discharge lamps are used where very high luminous flux, good economy and brilliant light are required. Fluorescent lamps are generally used for pathway lighting with their diffused light. LEDs are mainly chosen for quality of their long service life, compact design or various coloured lighting.
Low-voltage halogen lamps are hardly used for outdoor lighting due to their poor luminous efficacy and short service life. Modern metal halide lamps with ceramic discharge tubes boast good colour stability and rendition and feature integrated UV protection. They are available in warm white, neutral white and daylight white colours of light.
Fluorescent lamps are noted for their high luminous efficacy and long service life. The colours of light from these dimmable types of lamps are warm, neutral or daylight whites. They are available in linear fluorescent lamp designs and as compact fluorescent lamps with a diffuse lighting effect and are suitable for applications such as uniform and economical ambient lighting on pathways.
By adopting these simple yet effective basic fundaments of “Lighting Design for Monuments”, one can achieve the perfect illumination of monuments or artworks or sculptures during night by creating orientation points for visitors that are visible from a distance moreover bringing the history and culture of the structure to light.