The Visual Guide

The Visual Guide provides an understanding of:

  • Kelvin Colour Temperature
  • Colour Rendering Index
  • Beam and Glare

Colour Temperature and Colour Rendering

There are 2 very important aspects of light relating to colour which are often referred to but not always understood. 

Both properties of lamps have very different meanings and implications.

Colour temperature is in the unit of absolute temperature, Kelvin, noted by the symbol K.

Colour Rendering is the measurement of how light affects the appearance of the colour. 

How to Choose the Right Kelvin Colour Temperature?

Use the Kelvin Temperature Scale it can guide you in determining which fixture is right for each room

The influence of daylight on the human body

Studies have been undertaken as to how we react, physically and mentally, under certain Colour Temperatures. Such as the Circadian Rhythm The non-visual receptor in our eyes responds to light and regulates our levels of the key hormones: Cortisol, Melatonin and Serotonin. 

Serotonin is produced by the brain when melatonin levels are low. Daylight regulates these hormones, to ensure a good balance throughout the day. For office workers, good lighting design is required to have the same effect.

Which Colour Tone is best for you?

Colour temperatures higher than 3500K are typically used for commercial applications, as the light is bright and has a bluish daylight cast that can be harsh for home interiors.

In lighting designs, the feelings evoked by the memory of the sun’s colour are used to replicate and create an atmosphere or ambience which helps maximize things like:

Lighting is a very personal topic, as we all have our perspective and opinion on what we want from our lighting.

Speak to a BrightSpark about how lighting can improve the productivity of  your business.

How Different Colour Temperatures affect your "Body Clock"

Cool White

  • Reflects early morning and therefore we tend to concentrate more and have more energy.

Warm White

  • Reflects late afternoon when we are starting to wind down for the day and have a calmer feel.

Very Warm White

  • This mirrors sunset when we are relaxed and winding down for the day.

Why is colour rendering important for your business?

All lamps are not made equal and there is a range of LED lamps that have a CRI rating, from 50-95Ra, can have an impact on the way your decoration looks. 

Under a poor CRI, the room can lose its ‘spark’ and the area can look flat and the colours dim. 

CRI-before2 CRI-after2

How do you make sure the CRI is good enough?

The EU directive for lighting suggests that lighting should have a CRI of equal or greater than 85.

Colour Rendering Index

Lighting temperatures can range from infrared light to the kind coming from a skylight, all the way to ultraviolet light. You want to use lighting that will best illuminate each room.

The Colour Rendering Index is measured on an index chart of 0-100 Ra, where 100Ra = sunlight, i.e., replicating how the product looks under sunlight, and where the value of 0 means that the product 

The majority of indoor lighting schemes would be expected to meet a CRI of 80 or higher for most working activities

Speak to a BrightSpark about how lighting can improve the productivity of  your business.

3d-boxcri-2
CRI & Beam Angle

How do we know what CRI a lamp has?

The Colour Rendering index should be marked on every product – this is usually in 2 forms. 

It can either be detailed on the outer packaging/box or on the lamp/tube itself. Many manufacturers have differing forms of codes on their products, to ensure you order the correct item please do not hesitate to contact our sales team.

Speak to a BrightSpark about how lighting can improve the productivity of  your business.

How do we know what CRI a lamp has?

The Colour Rendering index should be marked on every product – this is usually in 2 forms. 

It can either be detailed on the outer packaging/box or on the lamp/tube itself. Many manufacturers have differing forms of codes on their products, to ensure you order the correct item please do not hesitate to contact our sales team.

CRI examples in different business environments

Gym lighting

Here the aim is for the members to feel energetic and get the most out of their sessions, so we want to feel energetic and, therefore, the lighting tends to be cool white to give the feel of early morning when we have the most energy.

Pub lighting

Here we want the customer to feel relaxed and stay, enjoy the atmosphere and, of course, spend more money, so a warmer feel to the lighting would be used.

Fast-food restaurant

Warm white lighting is used to give a friendly, warm, relaxed feel to the area – so when customers are placing their order, they are more open to upsell techniques.

Over the plastic chairs, cool white light is used so you eat your food quickly so you move on and free the space for the next customer.

Beam and Glare

Anything that produces light has a beam angle.

A beam angle sometimes referred to as “beam spread”, measures how light is distributed from the source of illumination onto a target area.

What is Beam Angle?

The beam angle refers to any light that falls within 50% of the maximum intensity the bulb is capable of producing. Any light outside of this angle is referred to as the “beam field” or “spill light”, which extends until the light has decreased to 10% of the maximum intensity. The level of brightness, or lumens, stays the same.

For example, if you take a torch and move it closer or farther away from a wall, the light changes. 

The closer you get, the more focused or intense the beam of light becomes. When you move the torch further away from the wall the beam becomes wider, but the level of brightness it produces hasn’t changed. It’s still just as bright, dispersing the light differently. 

So, if you wanted a brighter torch, you would need one with a higher lumen value, not a narrower beam angle.

Glare

Glare is typically caused by excessive and uncontrolled illumination’, whether that is from sunlight or artificial lighting. Discomfort from glare can be due to the source itself being in the direct line of vision, or from the source reflecting from buildings, windows or computer screens.


All of these forms of glare can be distracting for employees and can make it difficult for them to easily see and complete the task at hand. A well-designed lighting system will minimize glare and ensure visual comfort.

European Standard EN 12464-1 regulates the lighting of indoor workplaces, it should be taken into account at the design stage to avoid having to retrofit glare reduction after installation. Unified Glare Rating (UGR) is used to evaluate glare.

How Does UGR relate to Discomfort Glare?

The UGR rating helps to determine how likely a luminaire is to cause discomfort to those around it. 

A great example of this is when you face high-beam headlights when everything else around you is dark.