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Healthy Living

How to Improve Lighting

Light is such a basic phenomenon that we do not think about it till it goes out. Primal fears surface in darkness, or when we are unable to perceive light.

Poor lighting causes strain to the visual apparatus and causes general fatigue. It is advised that lighting should be thirty times the measure required for a job to be just done. We take a quick look at what kind of light is needed, how much and how to provide it in home environments.

Appropriate Lighting

Have sufficient light: There should be enough light to enable us to see details of objects and surroundings without strain. Fifteen to twenty foot candles is the accepted minimum light required for satisfactory vision.

Distribution should be even: Light of the same intensity is required over the whole field of work. Proper dispersal of light, without shadows is required for efficient vision.

Avoid glare: Glare is excessive contrast. This causes annoyance and reduces critical vision. Automobile headlights at night give off such a glare that pedestrians feel discomfort and are unable to adjust visually to the surroundings in the presence of glare. The disappearance of trees from roadsides, and the increase of glass fronted buildings, has increased the glare factor on roads. The same happens with polished floors, tabletops, or mirrors in houses. When direct rays of sunlight from windows or doors hit these surfaces, they give off a discomforting glare.

Avoid shadows: Shadows are inevitable. But too many sharp shadows confuse vision.

No flickers, please: The light should be steady. Flickering causes eye strain.

Opt for lights of the colour of natural light. The colour of light is not as important as the intensity. But since natural light has a soothing effect on us, the closer the colour is to natural light, the better it is for us. The background, usually walls and ceilings, should be of lighter colours and the floor, darker.

Enhancing Natural Illumination

Position of the house: It is better the house faces or is oriented to the north or the south. The light is not uniform through the day in the east or the west. Besides, the direct sunlight will heat up the room, especially during summer. The north-south oriented house has a better chance for uniform lighting.

Windows: A tall window facilitates greater penetration of light. A broad window enables better diffusion of light. The natural lighting is further influenced by the extent of sky that is visible. The ideal window size should be 10% of the floor space.

Colours: Light colours of the walls and ceilings reflect more light and make the room brighter. The lower portion of the walls and the floor should be darker.

Artificial Illumination

Overcrowded constructions hamper natural illumination. Buildings stand in the way of light. Apartment blocks pack as many dwellings together as possible. Walls are shared and window spaces are reduced.

For reasons of privacy, windows are smaller and curtains are used. We have begun to air-condition and soundproof rooms, where there is no scope of an open window. Therefore we have to resort to artificial lighting even in during the day.

Filament lamps and Fluorescent tubes are the two common options in household illumination.

The filament lamp is usually in the shape of a bulb, producing yellowish light. Hotter filaments emit white light. Filament lamps are available for a range of brightness. Decorative shades and chandeliers, provide illumination that is decorative. They emit plenty of heat.

The fluorescent tube: This is cool, efficient and consumes less power. It simulates natural light. The inner walls of the tube are coated to absorb the U V rays. This light is good for working or studying in. But this is unsuitable for decorative purposes.

The light we need

The eye is such an adaptable organ that it enables us to see in illumination that is close to darkness as well as bright daylight. Bright moonlight is measured as 0.1 lux and bright sunshine is measured as 100,000 lux.

To avoid eyestrain, it is recommended that illumination should 30 times as much as is required to just manage to do a particular job.

Here are some indicators of light requiremented by us.

Task Light Required
(in lux)
Casual reading 100
General office work 400
Fine assembly 900
Watch making 2,000 to 3,000


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