Layers of Lighting

Module: Module 1 - Principles of Lighting

Activity: Overview

In order to lay out a lighting design for a space it is useful to think of lighting as carried out in layers.

(1) General Lighting (Ambient Lighting)

This is the background lighting that bathes the entire space. It is fairly uniform and could be provided by fluorescent fixtures in the ceiling, HID downlights, and so on. The larger the space is, the more important it is to use energy-efficient lighting. In many spaces, there is no further lighting provided.

(2) Task Lighting

This is additonal lighting provided where it is needed. A table lamp or reading lamp is a perfect example of task lighting. One benefit of task lighting is that it is extremely efficient since you are only illuminating the thing that is important. In manufacturing areas there are workstations that rwquire a high level of light (e.g. inspection stations). It would be foolish and wasteful and dysfunctional to illuminate the entire are to the level required by the inspector.

(3) Perimeter Lighting

Perimeter lighting--you can think of it as illuminating the walls--serves a variety of purposes. It brightens walls to define the boundaries of the space and it makes a space look larger, creating a pleasant, comfortable environment. Lighting vertical surfaces (like walls) is critical to a successful lighting design. People's eyes come to rest on vertical surfaces; it is important to match the brightness (to an appropriate factor) to that of the horizontal work surface.

Sometimes you will use lamps specifically to illuminate the walls (wall wash fixtures). At other times, a judicious layout of the grid in the ceiling gets the first row of fixtures close to the wall and ensures that the walls are bright.

The two photographs below allow you to appreciate the impact created by illuminating walls. The space on the left looks dreary and uninviting. The space on the right has spring to life!

(4) Accent Lighting

Accent lighting produce visual interest and excitement by creating focal points. Paintings and plants, interesting features of the architecture--these can be highlighted and brought out with discreetly placed accent lights. PAR lamps, low voltage reflector lamps and now ceramic metal halide lamps are ideal for creating accents.

The photograph below is an example of dramatic effect created with low voltage halogen lighting. The lamps are mounted in fixtures that can move on tracks and be aimed at objects. Each fixture has a small transformer to convert the voltage from 120 volts to 12 volts. 12 volt tungsten filaments are smaller in size allowing precise beams to be created even using small reflectors.