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Light encyclopedia: All about light

This light encyclopedia covers the most important topics about light. So do you intentd to buy lighting and you're not sure where to start? No worries, we'll help you. Whether it's about light colour, energy labels or lumens, we explain everything. If you still have questions about certain topics after reading this blog, then we advise you to take a look at our blogs, in which we explain various topics.


A ballast is used to power lights, but also prevents them from receiving too much current and, therefore, limits the current. Certain lighting, such as fluorescent tubes and gas discharge lights always require a ballast. This also applies to certain PL energy-saving lamps and LED light bulbs and fixtures. You can choose from three different types of ballasts: conventional ballasts (EM), electronic ballasts (HF) and LED drivers. If you want to read more about ballasts,  you can read our blog.

Beam angle

A beam angle is the width of the light emitted from a light source. The width of the beam angle that you need depends on what you use the light for. Light bulbs with a wide beam angle emit the light at a wide angle, making them perfect for general lighting. Light bulbs with a small beam are more suitable for accent lighting, for example to illuminate art (e.g. paintings). Small light beams are recommended for high ceilings and wider beams for low ceilings. Are you still not sure which beam angle suits your needs best? Read our blog.

Bulb fittings

The fitting is the base of a light bulbs that forms the connection between the fitting and the light source. Which fitting you need depends on the type of light bulb. Always make sure you know which fitting you have. Often the number in the fitting indicates its diameter in millimetres. For the most common light bulb, the E27, the diameter of the fitting is 27mm. For a socket with pins, such as the GU4 or the GU5.3, the distance between the pins is 4mm and 5.3mm. See the examples below to see what the different fittings look like.







Colour code

The colour code is a combination of both colour temperature and colour rendering. This colour code is indicated by 3 digits in the product description, the product name or on the product's box. The first number indicates the colour rendering and the other two indicate the colour temperature. For example: 830. Here, 8 is a colour rendering of more than 80 and 30 is the colour temperature of 3000 Kelvin.

Colour Rendering Index (CRI)

Colour rendering or CRI is the measure of how well colours are rendered. The highest CRI value is 100. Nowadays, all light sources sold to households must have a CRI above 80. A CRI level above 90 is especially important for illuminating art, products or food.

Colour temperature

Are you looking for warm or cold lighting? And what's the indended purpose of the lighting? To illuminate the cosy living room at night or do you intend to use it in your home office during the day? Lighting with different colour temperatures has different areas of application. The colour temperature of lighting determines the atmosphere of the room. A low colour temperature is perfect for atmospheric lighting and a higher colour temperature is more suitable for offices in order to work and concentrate. The colour temperature is measured in Kelvin: the lower the value, the warmer the light. When the colour temperature is higher, the light becomes brighter. The colour temperatures are:

1800 - 2700K (very warm white)
3000K (warm white) 
3500K - 5000K (cool white)
6000K - 6500K (daylight)

Sometimes you can also choose tunable white and CCT, but what's the difference? When you choose tunable white, you can set the lighting yourself to any value between 2700K and 6500K, such as 2825 Kelvin. This can be done manually but also automatically, creating an even transition throughout the day. You can also set CCT (Controlled Colour Temperature) yourself, but not to any Kelvin value. With CCT, unlike tunable white, you have to manually set the colour yourself with a switch and you can choose from fixed values, such as 3000K, 4000K or 6000K. So you can't choose values in between, nor can you set the lighting to change automatically.

Would you like to learn more about colour temperatures? In this blog, we'll tell you all about it. In this blog, we help you choose the right colour temperature and read this blog if you need help choosing the right colour temperature for each room.

Dimmable lighting

Dimming means you can reduce the intensity of light. Light is emitted when electricity passes through a light bulb. When more electricity is used, the light emitted by the light bulb will be brighter. When you dim a light bulb, only a small amount of electricity passes through the light bulb, causing the light bulb to emit less light. With dim to warm light bulbs it's possible to dim the colour temperature. In order to dim a light bulb, you need a dimmer. LED light bulbs work best with a dimmer suitable for LED light bulbs. If you don't have a dimmer, smart light bulbs may be the best option for you. You can dim this light through an app or a remote. Perfect!

Direct current and alternating current

Direct current and alternating current are two common terms in electricity, but what's the difference? In direct current, electrons move continuously in the same direction. This is not the case with alternating current. The electrons move from the minus point to the plus point and back again. Both have a different voltage: 12V with direct current and 230V with alternating current. Sockets in Europe have 230V and light sources work with 12V or 230V. Lights with, for example, a GU10 or E27 fitting work on 230V and bulbs with a GU5.3 and GU4 fitting work on 12V. Please note: it's not possible to connect a 12V lamp directly to the 230V mains. For this, you need a transformer that converts 230V to 12V.

Energy labels

In September 2021, new energy labels have been introduced, replacing the old energy labels (A++ to E). The energy label indicates how energy-efficient the light bulb is. The energy labels range from A, the most efficient to G, the least efficient. With the new energy label, most LED lighting falls into class B, C or D.

Do you still want to learn more about the new energy labels? We tell you all about it in our blog.

Symbol Lampe

From 2021 you can find a QR code on the packages of light bulbs with the new energylabel, which gives you easy access to important product information.

IP code and IK rating

The IP code and IK rating indicate the degree of protection against external factors. IP means Ingress Protection and is indicated by two digits. The first digit indicates whether the fixture is protected against dust and the other number shows whether the fixture is protected against water. IP66 means that the fixture is protected against dust and powerful jets of water. The IK rating shows whether the fixture is resilient and this is indicated with 1 digit. When the number is higher, this means that the fixture has a higher level of protection. Waterproof fixtures are suitable for damp and wet environments. Usually outside lighting has the highest level of protection against dust and water: from IP65 to IP68. For bathrooms, a minimum IP rating of 44 is sufficient. On our product information page we explain more about IP and IK values and you can find the exact values and their explanations in the tables.

LED Lighting

LED means light-emitting diode. LED lighting works in a different way from conventional lighting and therefore has a longer lifespan. On average, LED lighting lasts around 15,000 - 100,000 hours. Compare that with the incandescent lamp (1,000), the halogen lamp (4,000 hours) or the energy-saving bulb (20,000). In addition, you save 70% in energy costs with LED lighting. Despite LED lighting being more expensive to buy, you save a lot of money in the (not so much) longer term. It's also a lot better for the environment, because these lights do not contain any harmful substances. These bulbs can simply be recycled to make a new generation of LED lighting. So you also contribute to a better and cleaner world.


The lifespan of a light bulb is measured in hours. If you want a light bulb that lasts the longest, choose LED lighting. How long an LED light bulb lasts depends on the brand and the lamp. On average, an LED light lasts between 15,000 and 100,000 hours. How many years a LED light bulbs lasts depends on how often you use the lighting.

If you have lighting in the office that is on for 9 hours during 5 days a week and you have LED panels that have a lifespan of 50,000 hours, then this fixture will last over 20 years.


The definition of lumen is: a unit for the total amount of visible light (what we see with the naked eye) coming from a light bulb or other type of light source. In other words, lumens equal light output. Before LED lighting was introduced, we chose our bulbs based on wattage. But wattage means nothing more than the amount of energy a bulb uses. So when choosing an LED bulb, always look at its lumen output.



Lux is also a definition for light output, but for the amount of light hitting a surface. When a light bulb indicates the amount of lux, it is usually in the centre of the beam where the light intensity is highest.


Recycle old or broken light bulbs and fixtures 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.


RGB lighting can be set to all colours of the rainbow, making it easy for you to choose the best colour and the best lighting for any occassion. You can easily pick the colours by using a remote control, for example. You can read more about RGB in our blog.


Sensor lighting is a perfect solution in large buildings where lighting does not need to be on all the time. Sensors react to heat, movement or absence of light and switch on the light when it detects any of these. Below you can see the different types of sensors that can be used both indoors and outdoors.

  • High frequency: detects movements, even extremely small movements. Suitable for offices, schools and as security lighting because the sensor does not need to directly 'see' things it will detect.
  • Twilight switch: detects the amount of daylight and adjusts the light accordingly. This sensor also switches on the light at dusk and off at dawn or during the day when there's sufficient daylight.
  • Motion sensor: detects movements and, unlike the high-frequency sensor, has to be visible as this sensor has to 'see' movements to detect them.
  • Passive infrared: detects differences in heat and movement of people or animals radiating heat.


You can't just connect every light to every socket. Light sources that work with 12V cannot be connected to 230V (the mains voltage), so you use a transformer. With a transformer, the 230V coming from a socket is converted into the 12V needed for the lighting. You can choose from two types of transformers: conventional and electronic. If you want to be able to dim your 12V lights, you need a dimmable transformer.

Do you want to read more about transformers? We tell you all about it in our blog.

UV light

Many older lighting technologies emit UV light. UV light has a whitening effect on the objects it shines on and is not suitable as general lighting in an office, for example, but also not for illuminating art or food. UV light is used to kill bacteria in ponds. You also find UV light in tanning beds, insect killers and areas of science. But you don't have to worry, as LED bulbs do not contain UV light.


Voltage (Volt) is a unit of measurement used to indicate how much voltage is on an appliance and is often written as V. The current coming out of your socket is 230V. Most lights work on 230V, but some lights work on 12V. In this case you need a transformer, which is explained under the heading transformer.


When choosing a light bulb, it's important to determine how much light you need. Watt is the unit of energy. Before the invention of LED lighting, we picked the right light bulb based on the amount of watts. The rule of thumb was: the higher the wattage, the brighter the light. However, this changed when LED lights were introduced. What's so great about LED lighting is that you use fewer watts. but you still get the same light output. Therefore, you have to pay attention to the amount of lumens when buying an LED light bulb.


Do you want to learn more about lighting? Read our blogs:

How do I choose the right light colour? 3 useful facts!

How do I choose the right beam angle?

Everything you want to know about LED

Anne - Last update May 2023