Light encyclopedia: All about light
In this light encyclopedia we have gathered the most important concepts about light. This blog is supposed to be of use for anyone who is in the process of buying new light for spaces like home, office, garden, garage, shop and other or someone who just wants to know more about light.
Here you can find easy and fast information on light concepts such as colour code, lumen and watt - everything in alphabetical order so you can find whatever you need in an instant.
What kind of light do you want? Warm or cold? Mood light or functional work light? Different colour temperatures have different areas of application. The kind of temperature you choose is very important in how a room is perceived. A low colour temperature is perfect for mood light and a high one is better for work environment and concentration. Colour temperature is measured in Kelvin. The lower the value the warmer is the light. The higher the value the more clear and crisp the light is.
Colour Rendering Index - CRI
Colour rendering or CRI is the measure of how well colours are rendered. The highest CRI value is 100. All light courses sold to households today must have a CRI above 80. High CRI value above 90 is especially important for illuminating art, products or food.
The colour code is a measurement that combines both colour rendering and colour temperature of a light source. The colour code is indicated by tree digits in the product specification, the product name or on the box of the product. The first digit stands for colour rendering and the other two for colour temperature. It can look like this: 830. In this case 8 is a colour rendering over 80 and 30 is the colour temperature of 3000K.
Dimming means decreasing the intensity or, in some cases, a colour temperature of light. Light is emitted when electricity passes through a lamp. The more electricity passes the more light is emitted. Dimmable lights create a dynamic and flexible atmosphere while also using less energy. To dim a lamp you need a dimmer. LED-lights work best with a dimmer adapted to LED lights, however, if you do not have a dimmer, Philips Dimtone can be dimmed without it. With Glowdim from Osram it is possible to dim the colour temperature.
Direct current & alternating current
Direct current is 12V and the alternating current is 230V. Standard wall sockets have 230V. Light sources work mainly with either 12V or 230V currents. Lamps with GU10 socket run on 230V and lamps with GU5.3 and GU4 sockets run on 12V. It is not possible to connect a 12V lamp directly into the wall socket. In order to power the light, you need a transformer which converts the voltage from 230V to 12V.
The energy label indicates how energy efficient the light is. Energy labels range from A++, the most efficient to E, the least efficient. A fixture with integrated LED-lights has the energy label A++ to A. Since 2016, all new fixtures need to have light sources with the energy efficiency A+ or higher.
IP & IK rating - is it waterproof?
IP and IK ratings indicate how safe a fixture is from outer effects. IP stands for Ingress Protection and is indicated with two digits. The first one indicates the fixture protection against solid objects like dust. The second digit is the protection against fluids. IP66 protects against dust and powerful water jets. IK is the proof against vandalism, like punches or any other mechanical impact. It is indicated by one digit from 0 to 10 (ex. IK07). The higher number the better protection. Waterproof fixtures are recommended for moist, damp or wet environments. Outdoor lighting should have the highest protection against solids and water, and therefore an IP rating between IP65 to IP68. For bathrooms and humid areas IP44 is recommended.
The lifetime of a light source is measured in hours. Choose an LED-light if you want a lamp with longer lifetime.
Light beam - accent lighting or general lighting?
Light beam is the width of the light emitted from a light source. The choice of light beam angle depends on the use of the light. Light source with a wide beam angle spreads the light throughout a bigger area, which is good for general lighting. Light source with a small light beam is better for targeted illumination, such as art piece. For high ceilings, a smaller light beam is recommended while for low ceilings a wider one is preferred.
Nowadays, the efficiency of a light source is measured in lumen per watt. per watt. Lumen is the unit of luminous flux emitted by a light source in a certain angle or direction. In short - lumen equals brightness. Before the modern LED lights, lamps were chosen depending on watt consumption, which was equal to brightness. However, when choosing LED lights it is more important to look at amount of lumens. The reason behind it is that LED lights are more energy efficient. Thus, they consume fewer watts but still offer the same amount of light.
The amount of lux of a light source also indicates the amount of light. The difference between lumen and lux is that lux also takes into account the space the light is spread across.
Your old or broken lamps and fixtures can and should be recycled! It can be done at a recycling centre or an environmental station. In most countries this kind of recycling is free, since an eco-tax is already included in the price of the product. Light sources are made with rare earth metals and electronic materials that are reusable. Older light technologies like fluorescent lamps contain mercury, and need to be handled carefully to avoid breakage and spread of dangerous toxins in the nature.
Sensor controlled lighting s a perfect lighting solution in large facilities where the light does not need to be on all day. Sensors react to heat, movement or absence of light and turn the light on if it detects any of these. These are the different types of sensors and they can be used both indoors and outdoors.
- High Frequency - detects movement, even extremely small. Optimal for offices and schools. It can also be used as safety lighting as the sensor does not need to directly “see” objects and can therefore stay hidden.
- Twilight Switch - detects the amount of daylight and adjusts the light depending on the amount on detected daylight. For example, it turns the light on at twilight and turns the light off at dawn or daytime when the natural light is enough.
- Motion Sensor - detects movements and need to be placed in visible areas so it can “see” the things it should detect.
- Passive Infrared - detects differences in heat and movement of humans or animals that emit heat.
The socket is the base of a lamp. This is the connection between the light source and the fixture you place the light in. The socket can be very different depending on the type of a lamp. Always makes sure you know which socket you need for the fixture before purchasing the light. The number in the sockets name indicates its diameter in millimetres. For the most common E27 lamp, the socket is 27 mm wide and a socket with pins like the GU4 or the GU5.3 has 4 and 3.5 millimetre between the pins.
Many older light technologies emit UV-light. It has a whitening effect on the objects it shines on and is therefore are not recommended as a general lighting in areas like offices, art galleries or food stores, partly because of its harmful effect on our health. UV-light can be used tanning beds, insect trap lamps and acts as disinfectors in pools and ponds. LED-lights are free from any UV-light.
Watt is the unit of energy. It is important to choose lamp based on the amount of light you require. Before LED lights, we chose the right lamp by looking at the amount of watt, since incandescent lamps with a higher wattage produce more light. With LED-lights, however, this is not true anymore. Their energy usage is much lower while the same brightness in maintained. As a matter of fact, an important specification when choosing an LED lamp is the amount of lumens.