Most lighting is delivered by the Sun Corporation and is thankfully free of charge. This is called natural light. Natural light has two forms:
- Direct light from the sun: Direct from the sun as its source, this light is bright, creates hard, black shadows and is generally white in colour, though at dusk and dawn the colour will be more yellow and red. Because of the sun's travel this light has a daily direction, (from east to west), as well as a seasonal positioning. (In winter the sun is lower in the sky, and rises and sets closer to north, than in the summer).
- Indirect sunlight from the sky: This is the light emitted by the entire dome of the sky. The sun illuminates particles in the atmosphere creating another source of softer light from the sky. Because this source is much larger than the sun itself, the light coming from it is more omni-directional. A cloudless sky will also produce a sharp light.
However on a cloudy day, the water particles filtering the sunlight will produce (an often more beautiful) softer skylight. The softness depends on the thickness of the cloud as does the colour which becomes bluer with more cloud. The different types of clouds which the sunlight travels through, or reflects from, will give indirect light it own colour.
Direct and indirect sunlight are always present together but not always in the same mix of intensity. At noon, on a clear, tropical, desert, summer day, the direct sunlight will be much stronger than the indirect light coming from the sky around. This causes shadows to be very deep and dark. This is high contrast.
On a slightly overcast, mid latitude morning or afternoon there will still be shadows but they will be quite soft. This is low contrast.
On a very overcast day there is no direct light at all, so there are virtually no shadows and the contrast is very low.
Direct light is:
- direct from a source (sun, light globe)
- hard, directional, and creates hard shadows i.e. contrast
Indirect light is:
- direct light filtered through a medium (clouds, lamp shade) or reflected off a medium (white wall)
- softer, less directional, softer shadows i.e. less contrast
Lighting direction is:
- highest on a noon summer sun
- lowest on a low morning/afternoon winter sun
Contrast is the difference between light and dark.
Light in the house
Applying the basics
During the day light enters our home through windows, doors, skylights and other openings. Inside, these openings become the source of the interior light.
Depending on the kind of light entering through the window this light will be hard (direct sunlight) or soft (skylight, cloudy day or reflected from next door's white wall).
To see we need light. To work we need good light. Good working light is bright, but not too bright. It is not too hard or directional. The shadowed areas should not be too dark i.e. the contrast ratio should not be too high. It should also be as white as possible (full spectrum white).
To achieve this, our light source windows should be large, letting in a lot of light.
The light coming through the window behaves like the light in the sky. If direct sunlight enters, the beam of light will be bright. Some of this light will fall on a wall and reflect around the room becoming indirect light. However, the ratio between bright sun light and other light will be high and shadow areas will be dark.
If there is another window, preferable on an adjacent or opposing wall, the light will be more omni directional, filling in the dark shadows with soft light.
At night or on dark days we have to light our homes artificially. Rather than replicating the natural daylight situation by placing large artificial lights where the windows are, we place smaller lights more selectively where light is needed.
Different lighting sources and their light
The previous basics also apply to artificial light.
A light globe of any kind is a source, like the sun. Some globes like old fashioned filament lamps and projector globes give sharp, hard light. Some globes give a softer light because they have a reflector built in, like many 12V globes. Other globes are softer still because they have softening medium around them, like fluorescent sources, softer again when they are long fluorescent tubes.
The globe may be filtered through a lamp shade which also makes the light softer and perhaps coloured. It may reflect and bounce from a secondary surface like a wall or ceiling. Regardless how the light is generated by the artificial lighting unit, the emitted light behaves in principal like sunlight; it has a hard or soft quality and has a colour.
If noonday sunlight is considered white (full spectrum white):
- Fire light, (like a candle), is very much redder or warmer.
- Incandescent globes produce a less intense but still warm glow
- 12V halogens are a little whiter again
- Fluorescents are manufactured either as warm whites or daylight globes or in any other colour.
- Other discharge lights (like street lights) are orange or yellow depending on the gas used n the globe.
- LED lights are very blue, like daylight.
But ultimately all artificial light can be manipulated (like "Varilights" on a dance floor: any colour, any beam, any time.)
Categories of light
Artificial light can be divided into three categories according to its use.
Ambient lighting provides a general purpose lighting level allowing us to perform basic functions. Ambient lighting is generally soft and low in contrast. It is the basic light level in a room or corridor.
Task lighting provides the necessary light to perform specific work. It is often more directional and localised to where the task is performed. It is additional to ambient lighting but higher in level and perhaps different in colour.
Feature lighting provides accents to certain places or objects and can create a certain mood. It is decorative and works in addition to ambient and or task lighting.
Historically most artificial lighting is done from the ceiling, by means of:
- ceiling fixtures
- hanging pendants
- ceiling mounted fluorescent tubes
- recessed 12V halogens (more recent).
While these high positioned sources are generally quite good for ambient lighting purposes, they are not necessarily most effective for task lighting. Like a high noon sun, such sources in combination with our body and hands have a tendency to create dark shadows on a work surface. Nor are these deep shadows very attractive on any face.
The above-mentioned categories can also be applied to any natural lighting situation.
To know precisely the use of a room will help greatly in properly designing windows and window placements and in designing artificial lighting plans.
Natural Light in the Kitchen
The most important areas for good light are the work areas- bench tops and stove. Ideally light falls on this area from two directions.
A window behind the bench top is great light source. A long, narrow, clear or milk glass window between bench and cupboards will give a very workable light, especially if the glass is frosted (emitting a shadow-less light). An opening hopper window will also provide ventilation to this area. In addition, one or more windows to the side are preferable to avoid badly shadowed areas.
If the kitchen also functions as a day room or dining room, additional light would be required for an island bench or table. There may already be enough light from the windows near the work area. Perhaps a skylight can help to read at a breakfast table.
The secret is to analyse what and where activities are performed.
Artificial Light in the Kitchen
The artificial light required at night can be designed to work as well as the natural light did during the day.
It is possible to replicate the light from the bench window with 12V halogens lights built into the underside of the cupboards above the bench. Another very usable light (but hardly used) source is strip or rope lights that are attached underneath cupboards or shelves. This one direction source alone may probably not be enough. Additional light may have to come from either the ceiling, perhaps with lighting pendants hung just above eye level with suitable shading, or ceiling recessed spotlights crossed left to right and right to left. In this way the light direction is not completely from the top but more from a 45 degree angle.
A similar plan could be used for a dining table or additional work benches.
To provide ambient light in the kitchen, (or any other room), a ceiling mounted unit could also be used. (In the past this would often have been one or more fluorescent tubes).
A better effect would be created by recessed spotlights with the spots directed onto (light coloured) walls. These walls then become the new sources, softer in quality and lower in direction. Another way to achieve this effect is through the use of wall fixtures.
Ambient and task lighting, (both together and individually), will easily combine with any kind of feature lighting to create a comprehensive lighting plan.
The Home Office
In a home office the most important area is the desk which should receive light from two directions. As in the kitchen, the desk against a window with another window to the left (for a right-handed person) is an ideal situation.
At night a desk lamp in addition to some ambient light will provide enough task lighting.
Living rooms, media rooms, rumpus rooms all have their very specific functions.
We like our living room to be warm, inviting, and atmospheric. To achieve this we need a certain amount of ambient light, probably less than in a kitchen, home office or other task related room. In fact, too much broad ambient light may make it very difficult to create a certain mood because the essence of mood lighting is the contrast between dark and light, and warm and cool.
Ceiling lights such as mounted halogen lamps spotted on pictures and objects will often spill enough onto light coloured walls to provide sufficient ambient light. A reading lamp here and there will also help to provide some task lighting. Darker coloured walls will absorb more light than they reflect. In this case more specific ambient light may be needed. And when the walls are a strong specific colour, this colour will be reflected throughout the room. Blue coloured walls may produce blue, cool light which could be counter productive to a warm feel.
If the living room is also used to watch television it is good to have ambient light behind the set. The older CRT tubes and the current plasma televisions are highly reflective and the image quality will suffer from reflected lights and brightly lit rooms. LCD (matte) screens are more forgiving in this respect. For this reason media rooms often have darker walls with low level ambient light from hidden sources.
The vanity basin is the most important area in the bathroom. This is the room in which we scrutinize ourselves. We could do ourselves a few favours here with flattering light. Avoid any hard, high angle ceiling light falling on the face, for it will create deep shadows in the eye sockets and under the chin.
If this light is centred in the room, behind the person in front of the mirror, no light will hit the face other than a little reflected from the mirror or the walls. If this light is also an older- type fluorescent, (with a built-in green tinge), our skin will look very sick.
A better and more flattering light for the vanity are two wall fixtures either side of the mirror, (reminiscent of the rows of globes around the mirrors in a theatre dressing room). A typical shaving mirror has a light built into the lower part of the mirror. If any additional light is needed any soft light source bouncing off white tiles will complement the picture.
For daytime lighting frosted glass windows either side of the mirror, or a mirror in front of a large, frosted window, will give flattering, soft, shadow-less light. (It is the dark shadows from hard light which make wrinkles stand out.)
Bedrooms, because of their specific function, do not need large amounts of light, (unless they perform double functions like work room or home office). Bedrooms benefit from mood enhancing feature lighting but most important is the bedside lighting for reading, which ideally is just above head level and to one side.
This can be a simple bedside table lamp or, in order to save space, something recessed (bearing in mind that the purpose for this light is most often reading). Ceiling mounted down lighting is very likely to shine directly into the face of a person lying in bed and therefore not very appropriate. Something just above head level off to one side will be far more satisfactorily. A small spotlight on an adjustable arm is very useful here for it can direct the light away from a sleeping partner.
Two such lamps, wall mounted in the centre of the bed, will work even better for the light will be directed away from the other side of the bed.
Ceiling mounted down lighting is very likely to shine directly into the face of a person lying in bed.
If the bed is precisely positioned in the bedroom it is possible to plan lighting switches alongside for easy night time access.
If watching television is a pre-sleep pastime, like in a media room, it is good to have some ambient lighting on the wall or ceiling behind the screen.
For daytime lighting it may be sufficient to have only one window in the bedroom.
If there is a choice, bedroom windows should not face the easterly rising sun. Equally undesirable could be skylights unless they are the multi talented kind with built in light controls.
Some Finer Details
For both natural and artificial lighting, control of light is essential.
Curtains on windows have different densities to soften the light, provide some privacy, or completely block out light. Louvered screens enable the precise control of light entering a room. Adjustable awnings may block the direct sun and also act as an indirect soft source over a window.
Dimmers on artificial light sources allow the light levels to be adjusted to suit a particular mood, changing a room from a richly lit dining room into a suitable media room.
Computerised lighting, like C-bus systems, can do all of these things and much more, delivering automated options through PIR sensors, timers, ramping dimmers, memories, remote control access.
The same rules that govern interior lighting apply to the exterior spaces.
Exterior task lighting primarily provides safe night time access, around front door, garden paths and pool areas.
The old large-sourced ambient lighting, (like multiple high wattage filament globes or spotlights) should be avoided. There are now many other more energy efficient and effective choices. Small 12V 10 watt halogen fixtures over or near the front door or along a path or staircase, will light enough of the traffic area to allow safe passage. The new extreme low wattage LED lights will do the same thing even more efficiently.
Path lighting is best mounted on a wall or post, well below eye level, so that the source at no point blinds the traveller. Any close light source at night has a tendency to blind because the eye's pupil has adjusted wide open to very low levels.
When this task lighting is augmented with some feature lighting, (accenting particular plants, water features, stone walls), the path to the house becomes a passage of discovery.
Unlike interior rooms, the garden generally does not have a ceiling, so most fixtures would be mounted in the ground, providing up-lighting for plants and walls. While exterior feature lighting can be very attractive, one must be energy conscious and selective when deciding what to light. Not the entire garden needs to, or should be, lit up. Also consider how the exteriors lights impact on the neighbours. Some people (possible rightly) think that excess garden lighting is light pollution. Infrared sensors that turn lights on when needed are a worthwhile consideration.