Lighting Basics

A Brief Introduction

We are starting to embrace the importance of good lighting.  Eighty percent of our decisions are based on what we see. Seeing is the interaction between the eye, the object viewed and light. Light, determines how we perceive the object in view.  So SEEING REALLY IS BELIEVING!!! 

Lighting controls visual impression. In order to achieve a desired environment, knowing how to use light and lighting is essential. Even with smaller budgets, the impact can be significant – remember, in the dark, it only takes a flashlight to create a visible monster.

Know your lights

Since we can acknowledge the importance of how light cascades on an exposed object, we need to educate ourselves on how our choice of lighting interacts with the object when it comes to color representation.   

It is important that a lighting environment enhances the objects being illuminated to make them most appealing.  The red color of the tomato, for example, must be vibrant to appeal to the customer in the grocery store.

Quality, not quantity of light

Elements like color of light, degree or beam spread and brightness are also important factors to the environment and the object being illuminated.   A display may be made dull by a poor choice of lighting. The quantity of light does not create good lighting.  For example, a large floodlight provides the quantity of light needed for a night time outdoor ball game, but would simply be the wrong choice for most exhibit or retail displays. Instead, to catch our attention, narrow beam spotlights should be used to make products or areas “pop” or stand out while playing down the surroundings.  This type of lighting creates contrast through interaction between darker and well illuminated sections.

Energy efficiency 
Energy efficiency is increasingly important in all lighting decisions, both for economic reasons and for sustainability reasons.  With the development of emerging technology, it is possible to make good lighting choices for a project for illumination purposes, as well as for the well-being of our planet.  Ordinary light bulbs produce 95 % heat and only 5 % light and often require additional cooling units, which make them quite inefficient when it comes to energy consumption.  There are many options today that allow for a more energy efficient lighting solutions.  More information on this subject can be found in the Tools and Products section of this report.

Light – not only for exposure

Light can make a display or retail environment more competitive and attractive, but it is also a workplace where staff and visitors should feel at home. Research shows that our sight grows weaker as our age advances. A 60-year-old requires a lot more light than a 20-year-old in order to experience the same brightness.  At the same time, the 60 year olds eyes are more sensitive to sharp light, which is why properly placed sources of light are of the upmost importance.

Light and Vision

What is Light?

Describing and understanding light requires that we understand a few key terms. Below are short descriptions of five commonly used terms and a short introduction to them.

Color temperature K = Kelvin

Color temperature describes how light appears when the human eye looks directly at the illuminated source. Color temperature is measured by a unit called the kelvin (K), a scale that starts at absolute zero (-1273 degrees C). Imagine heating a bar of steel and observing the color of the bar at increasing temperatures. At some point the bar will appear to glow a dull red. As heat is added, the dull red turns to yellow, then to white, then to bluish white and finally to blue.
A light bulb that produces light perceived as a yellowish white color output will have a color temperature of around 2700K. As the color temperature increases to 3000K - 3500K, the color of the light appears less yellow and more white. When the color temperature is 5000K or higher the light produced appears bluish white. The color temperature of daylight varies, but is often in the 5000K to 7000K range.
It is important to note that color temperature is not the same as color rendering. The color temperature of a light source does not describe or predict the ability of that light source to render color accurately. 

Lux = Luminous intensity

Lux is the measure of illumination on a surface at a particular distance from the source of the light.  It answers the question – how well is this object illuminated at a particular distance from the light source?  For indoor work, a luminous intensity of 500 up to a 1000 lux is common. In our homes, the intensity is often around 200 lux. These numbers pale in comparison to the luminous intensity on a sunny day, which can exceed 100,000 lux!

Candela (cd)

Candela is the measurement of light brightness in a certain direction. Knowledge of the Candela of a light source allows us to calculate how much light will reach a specific surface. Candela answers the question – How well is an object illuminated at a particular distance from a light source?

Lumen per Watt (lm/w)

Lumens are a property of light that more and more people are aware of when choosing which type of light source to use. It measures how effectively a lamp uses the supplied energy (watt). An effective light source will turn the supplied energy to light, while a more ineffective one will turn it into heat.

Color rendering (Ra)

Color rendering describes how a light source makes the color of an object appear to human eyes and how well subtle variations in color shades are revealed. The Color Rendering Index (CRI) is a scale from 0 to 100 percent indicating how accurate a "given" light source is at rendering color when compared to a "reference" light source.

The higher the CRI, the better the color rendering ability. Light sources with a CRI of 85 to 90 are considered good at color rendering. Light sources with a CRI of 90 or higher are excellent at color rendering and should be used for tasks requiring the most accurate color discrimination.

It is important to note that CRI is independent of color temperature (see discussion of color temperature). Examples: A 2700K ("warm") color temperature incandescent light source has a CRI of 100. One 5000K ("daylight") color temperature fluorescent light source has a CRI of 75 and another with the same color temperature has a CRI of 90. 

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Tools and Products

The Tools

Good lighting application engineers and good tools can create wonderful illumination results, even with small budgets. Product development in the light area may be greater than even before.  The choices that can be presented for consideration offer many different qualities, types and price points of lights today.

 

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 Incandescent light bulbs

Incandescent light bulbs, or lamps, have always had a good rating on color rendering index (RA), but are now making way for a new generation of energy-efficient light sources. Why? Because only 3% of the energy they consume becomes light – the rest becomes heat radiation.

 

 

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Line voltage halogen

Used mainly in home lighting and more common in Europe than the U.S. Only 6-7% of energy consumed becomes light. Approx. 10% less system efficiency than low voltage halogen bulbs, mainly due to a larger burner arrangement inside of the lamp. No transformer is required.

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Low voltage halogen lamps

Widely used in exhibition and retail lighting during the 1990s. Good color rendering, but consumes too much energy to be suitable for the modern retail lighting of today. Lamp lifespan is also too short. Requires a transformer to operate. Only 6-7% of energy consumed becomes light.

 

Compact fluorescent lamps, CFL

Fluorescent lamps are good for ambient (general) lighting but are not the ideal choice for showcases. There are optical difficulties in controlling light flow from the lamps as there are no reflectors or optics integrated into the lamps. Requires a ballast to operate, which is usually built into the lamp. Approx. 20% of energy consumed becomes light.

Linear fluorescent lamps

Many types.  Nowadays, T5 and T4 are most common. Linear fluorescent lamps are good for ambient (general) lighting but are not the ideal choice for showcases. There are optical difficulties in controlling light flow from the lamps as there are no reflectors or optics.  Requires a ballast to operate which is usually built into the light fixture. Approx. 25% of energy consumed becomes light.

-->Discharge lamps (HID)

Single-ended, double-ended or also available as PAR lamps. Currently the most widely used light sources in European exhibition and retail lighting. Double-ended types usually have a longer lifespan, but difficult to design narrow beam spread reflectors. Approx. 25% of energy consumed becomes light. Requires electronic ballast to operate which is usually built into the light fixture.

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”PAR” HID-lamps

Widely used in North America, but have a limited lifespan due to their design. Difficult to use for accent lighting applications because of inherent optical limitations in controlling light flow. Approx. 15-20% of energy consumed becomes light due to the optical design of the reflector.  Pros & cons: can be used in less expensive light fixture, but more expensive lamps.

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Products

Here you can find out more about which products lighting
professionals use in trade shows, stores and other locations.

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Arm lights for exhibitions and display systems

Arm lights are suitable for use in temporary installations or when ceiling height does not allow for other types of lighting to be installed. Can be mounted on a permanent wall section or on portable display systems.  

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Track Lighting Systems

Tracks allow the user to connect several lights to a track with the flexibility of moving the light along the track where needed. Great flexibility in the event that displays are reconfigured over time.  Tracks can be used wherever needed for accent and ambient lighting.  Surface mounted, recessed or suspended installations are possible.

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LED

LED (Light Emitting Diodes) can also used, but remember – cooling is of the utmost importance to ensure the longevity of the LED.  High quality fixture have custom heat sinks incorporated into the fixture to achieve the necessary cooling.  Available in various color temperatures of white as well as color changing versions.

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Spotlights

Spotlights are a flexible and efficient way of focusing light where you need it most. Spotlights draw attention to your message and highlight your products.

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Down Lights

Down lights create ambient (general) lighting. Pull-out and rotational down lights can also be used as spotlights. Light levels should not differ by more than ~30% at any point across the floor.