If asked how to cast the best possible light on your office, we would suggest the following ten rules for you to observe when planning your lighting system.
What was the rule again? "General room lighting serves to illuminate a room effectively without producing direct or reflected glare by taking into account good contrast and colour reproduction and balanced luminance requirements." Sounds very reasonable indeed. Only how is it best achieved?
1. Added light does not always mean improved visibility
It is generally true that a considerable amount of light improves performance and that low light tends to have a calming effect. Generally speaking, it has been proved that older workers need more light. But it is necessary to distinguish between different activities. While a higher lighting level is recommended for reading a document, the same level of light is of disadavantage to reading information on a computer screen. This is due to the reduced contrast between characters and their background.
2. Watch the harmonious distribution of brightness
The level of lighting does not reveal anything about the distribution of illuminances on different surfaces. The so-called degrees of reflection should be chosen in a way to avoid excessive differences of luminance between the work surface and surroundings. Balanced distributions of luminosity make a room interesting and have a stimulating effect.
3. Avoid glare
Glare not only has an immediately disruptive effect but also reduces vision considerably. Therefore luminaires should limit glare to the extent possible – particularly for computer work.
4. Contrasts facilitate visibility
This point is extremely important: The lower the contrast, the poorer the perceptibility. The only correct solution is to increase illuminance. A word of caution, though:
Higher levels of light reduce contrast, which causes problems particularly for computer workers.
5. Watch the correct direction of light incidence
We all know this phenomenon: Wrong angles of light incidence cause reflexes which reduce contrast. Moreover, the incidence of light also affects shadows and consequently lighting balance and depth vision. In this regard it is worth noting, for instance, that the light from ceiling lamps with a high percentage of directional light should fall on a workplace in an oblique angle, i.e. laterally.
6. "Good" shadows will sharpen vision
Diffuse light without shadows – think of fog, for instance – loses its three-dimensional quality. Hard shadows, on the other hand, can make a dramatic difference to spatial impression and may even represent a safety risk. "Good" shadows are produced by the right mix of both diffuse and directional light as these shadows will improve spatial vision and orientation.
7. Watch the bright sides of light
Each source of light emits its specific colour spectrum – its specific light colour, terminologically speaking. In this regard, daylight is characterised by a balanced quality. Incandescent light bulbs, on the other hand, contain a relatively high level of red colour. Offices should use warm white and neutral white light colours with colour temperatures between 2,500 and 4,000 Kelvin.
8. Natural colours
Offices are among those work environments where natural colour rendition is important. More exacting specifications are only applied to museums. For that reason, characteristic quality features of lamps include their colour rendering properties!
9. Light creates an atmosphere
We did not know until a short while ago that pleasant lighting is very important for work and productivity. Contributing factors in this context are not only aesthetic qualities and the placement of luminaires but also such properties as reflection, colour and wall and furniture materials.
10. Energy saving important as ever
Deliberate, efficient handling of energy has become an obvious must today, even when planning lighting concepts. For that reason, people increasingly opt for energy-saving lamps and electronic control gear. Moreover, it is worth paying attention to high efficiency of luminaires. Finally, considerable savings can potentially be achieved by targeted use of daylight and effective control of light systems.
Last, but not least, what matters is the harmonious balance between natural and artificial light. Good lighting concepts envisage a high percentage of natural light. Not to forget that lawmakers require compliance with specific minimum standards – particularly when it comes to computer workplaces...