Buildings today, are not just shelters or good-looking habitable sculptures, nor are they only an organization of space and form. Today, buildings are more like a living organism, with various systems integrated together to function harmoniously and respond to its surroundings and to its users. Some common examples of such integrated systems are; carbon dioxide monitoring to control HVAC for better air quality and energy efficiency; automatic shading devices that respond to direction of sunlight, time of day and season; automated building security systems etc. Architects now have greater responsibility of not only being designers but also being managers and integrators, to ensure a smooth transition between all these working systems. As design of buildings has become more comfort driven than function driven, many new specialty fields have evolved; lighting design is one of them. Lighting design encompasses design of light for visual function, visual comfort and visual aesthetic. This article looks at these three aspects and aims to explain the role of the lighting designer in integrating the three to seamlessly enhance or stunningly augment architecture.
1. Visual Function
The functional aspects of lighting design involve achieving the right light levels and creating an energy efficiency design.
Light levels: The human eye can adapt to a very wide range of light levels however, a minimum light level is required to execute certain tasks. Light levels measured in Lux or Footcandels is the amount of light arriving at a task plane. The task plane is the imaginary horizontal, vertical or slanted plane at which the task is executed. To achieve the right light levels for a given task or multiple tasks in a given space the lighting designer may design one or many lighting systems that work together. Light levels can be calculated either by manual calculations or with the help of computer software. Today computer software enable lighting designers to model a space with the right surface reflectances, colors and textures. Lighting fixture photometric files are incorporated into the 3D model to calculate the exact quantity of light arriving at any plane.
Energy Efficiency: Energy efficiency can be achieved by a prudent choice of lighting sources and control systems. High efficacy (efficacy is the ratio of light output in Lumens to energy used in Watts) sources like fluorescents, compact fluorescents, LEDs and metal halide can replace low efficacy sources like incandescent, sodium vapour and mercury vapour wherever appropriate. Control systems can integrate occupancy sensors and photo sensors to turn on off or dim lighting fixtures depending upon usage and quantity of available natural light.
2. Visual comfort
Visual comfort is one of the most important aspects of lighting design which tends to get overlooked when a professional lighting consultant is not involved. Visual comfort involves eliminating glare, creating the right contrast ratios eliminating or even sometimes creating shadows to create a comfortable visual environment.
Glare: Control of glare can be achieved by using the right light fixtures at the right locations, and most importantly by using the right finishes. Distribution of light is not just a function of the photometric distribution of the light fixture but also a function of the composition of the space and its surface finishes.
Shadows: In certain environments shadows can hamper visual comfort or visual function or sometimes both. For example, office environments must be shadow free. Office lighting systems must create a bright luminous visual environment. On the contrary, high end retail stores rely on shadows and high contract ratios to create dramatic and sophisticated environments
3. Visual aesthetic
In a space, light can be used to highlight elements or light can be the element of highlight. This choice could be drive by a design direction to seamlessly integrate light into the architecture or by a design direction to use light to create a distinct impression on the occupant or user.
Highlighting elements: Choosing which objects of art or architectural features to highlight and how to highlight them in a given space contributes to a visual aesthetic. Features can by up lit, down lit, washed with light, grazed with light, backlit or a combination of these can be used.
Design element: One of the many ways to use light as a design element is to design light to be dynamic. With the aid of today’s technology this dynamism can be achieved by color changing lights, moving lights, moving patterns of light projected on surfaces, turning on and off sequence of lights in a pattern etc. The dynamic quality of light can be used very subtly to create different ambiances in a space, or can be used very stunningly to attract attention to entice the human mind.
And Finally Integration
A good lighting design flawlessly integrates the above three aspects. Light is, in a sense, layered on top of each other to create this integration. For example; in a restaurant one set of lights could aim only on the tables to give enough light for people to see their food. Another set of lights in the form of light coves or decorative pendants can contribute to a soft ambient glow which enables people to see each others faces without creating harsh shadows. Another layer could be accent lights that highlight art work on walls or free standing works of art creating a visual terminus or areas of visual interest. Another set of light fixtures could be designed to direct people to entries, exits, restrooms and other such functional areas. All these layers when integrated through appropriate control systems that can switch on, off or dim, work subtly to create the right ambiance and provide the right light levels.
Lighting design is thus a true integration of science and art. Some of the best lighting designs have been in projects, which integrate light, lighting systems and architecture so well that the light by it self goes unnoticed. On the other hand, other great lighting design projects have been those in which light has played an important role in creating a lasting impact. Light is necessary for human function, it has the power to affect human mind; it has the ability to create dimension; it has the strength to stir emotion.
“An artist uses a canvas to paint on, to express, to give dimension to emotion; Color is his medium. Similarly, for lighting designer space is the canvas and light is the medium. It is up to the lighting designer to use this medium to bring architecture to life.”