How Light Works: The Ultimate Guide

When you’re starting to choose lighting for your home, it can be tough to know where to begin, even if you’re certain of the style you’re looking to create in your home. With so many different lighting options available, and lots of variables between the different types of bulbs, it can be pretty mind blowing. Through this post, we’ll take you through the different categories of lighting that you need in a room, and the types of fixtures that you can use for each category. From there, we’ll cover the important issue of light bulbs, since they’re pretty complex, and understanding how they work makes buying them much simpler.

We’ve written this post with absolute beginners to lighting in mind – those who are setting out living on their own for the first time, new home owners, and those who have previously ‘made do’ but are now ready to create a stylish home that they can be proud of.

 

How light works a beginners guide light bulb sketch

 

What different types of lighting are there?

Where once we would have relied solely on the ceiling light to provide all the light in a room, today designers and lighting experts recommend having a range of different lighting available in a room – with at least one from each lighting category, to allow for optimal amounts of light for all the types of activities that may take place in the room. The main categories are ambient lighting, task lighting, and accent lighting.

As an example, in a bedroom:

  • Ambient lighting allows for getting dressed and moving around
  • Task lighting would allow for reading or for applying makeup
  • Accent lighting may be used to illuminate wall accessories, behind a TV or an aspect of the room’s design

 

Ambient lighting

Ambient light completely fills the room with light, and allows you to use the room as if it is daytime. It is often provided by the ceiling light in the centre of the room, but there are other types of lighting that can contribute to ambient indoor lighting.

It may be the case that producing the optimal amount of lighting requires a number of lights to be used at the same time.

 

Task lighting

Task lighting does exactly what it sounds like – it produces light for specific purposes. This could be for reading, cooking or for studying. Task lighting can be provided by a range of lights, including:

The type of task lighting that may be required is likely to differ from room to room and between the type of activity that it is needed for. For example, a desk lamp that is only used with a PC, or under-counter lights in the kitchen may be able to be a fixed type, whereas for craft activities, a lamp with a moveable head may be desirable.

 

Accent lighting

Accent lighting can take many forms, but is primarily there to highlight an accessory such as artwork or an architectural feature. This can be provided by lots of different types of lights:

Since accent lighting is there to highlight, then simpler light fixtures can help to keep the focus on the feature.

 

scene accent highlight lighting example in an art gallery

 

What type of lighting fixtures should I use?

The decision about which lighting fixtures you prefer is a personal one, and should be based on the type of look you are aiming to achieve in the room – but having at least one (if not more) of each type of lighting means that you’ll have the flexibility, and will be able to create the brightness that you need at any given time.

 

Ceiling lighting

Ceiling lighting is often the first lights that get chosen when moving into a new home. They tend to provide the general illumination in a room, but also add to the styling of the room.

While your personal preference, and the style and visual weight will ultimately guide your choice of ceiling lighting fixture, there are approximate calculations that you can use to narrow down the type of fixture that will work best in the space.

Working with the dimensions of your room in feet (rather than centimetres), add the number of feet in the width to the number in the length. The answer will give you the number of inches that your light fitting diameter should be. For example, if your room is 6 foot by 10 foot, the optimal size of light fitting would be 16 inches – which is about 40cm.

If you’re choosing statement lighting such as pendants that hang from the ceiling, the first thing to do is to get your tape measure out. It should go without saying, but you will need sufficient clearance underneath the fixture to avoid breakage and potential injuries. When hanging feature lighting from the ceiling, it is essential to have a minimum of two metres clearance between the floor and the bottom of the fixture (and if some members of the household are particularly tall, maybe a little more). If you’re hanging pendant lighting above dining tables, there should be at least 65cm between the table and the lighting fixture.

 

Wall lights

Wall lights can be used for all kinds of purposes – either to add to ambient lighting, as task lighting or as accent lighting – as well as providing a decorative accessory in a room with simpler styling. The function of the wall lights will influence the type of fixtures that you choose, while the style of the room will influence the type of wall lights that are chosen.

Where wall lights are used for effect, there may be a number of wall lights used – either paired, or in a series – or they may be positioned in an unusual spot. Using wall lights with colourful shades, and matching them with ceiling lighting can help to tie the overall look and feel of the room together, particularly where other accessories in the room coordinate.

 

Lamps

Whether you are choosing floor lamps, table lamps or desk lamps, as with wall lights, you’ll make your decision based on the size of the room, what category of lighting it is providing, and what activity the lamp will be illuminating.

Depending on their size, table lamps may contribute to the ambient light in a room, or may be purely used as task lighting – for example, for reading, or as a portable lamp that can be used for sewing or other types of crafts. Since more of us are using electronic devices for reading today (and are attached to our phones too), many styles of lamp now include USB charging points as part of their design. Where lamps are used for reading, dimmer switches are desirable – since this allows for better lighting throughout the day and night, when different levels of lighting are appropriate.

When choosing a table lamp:

  • Be sure that the bottom of lamp shade is approximately at eye level when seated, so that the bulb doesn’t shine directly in your eyes
  • Situate the lamp close enough to illuminate the task sufficiently
  • If the room has people walking through it often, then ensure your lamp is stable, so to prevent it tipping over
  • Ensure that the relative proportion of the lamp is appropriate – it should be no more than one and a half times the height of the item furniture that it sits on

When choosing a floor lamp:

  • As with table lamps, ensure that the lower edge of the shade is at eye level when seated
  • Avoid obstructing the view of décor such as artwork, as well as between seating locations
  • The smaller the room, the smaller the lamp should be
  • Keep safety first – if the floor lamp is likely to become a trip hazard (especially for children or elderly residents) it isn’t the right one

 

table desk floor lamp lighting

 

What type of light bulb do I need?

Once you’ve established the type of light fittings that you’re going to use in a room, and you’ve decided on the exact ones that you’re going to buy, you’ll need to choose your light bulb. Not all light fittings will have bulbs sent with them, and where they are, the bulb may not be to your preference. Choosing a light bulb isn’t always easy or straightforward either – since there are a number of variables that you’ll need to consider.

 

Choosing the right light bulb

If you’re replacing a bulb in an existing light fixture, the rule is to replace like with like – especially when it comes to the type of fitting. But the fitting isn’t the only thing you’ll need to consider. You’ll need to think about what the light is for (is it for ambient, accent or task lighting?), and what shape suits the fixture, as well as the cost both of the purchase, and in the longer term. Let’s take a look in more detail.

 

Fitting

While there are plenty of different types of light bulb fitting, when we’re looking at domestic light fittings, there are three main types that prevail: bayonet, screw cap, and pin and push-fit base bulbs. Generally, with these types of light fixtures, it should be easy to find a bulb that will suit.

When changing a bulb, you’ll need to find the same type of fitting for the replacement. Although adaptors are available, they should rarely be required, since different types of bulbs are so easily found today, especially from lighting specialists.

But establishing the fitting of the bulb is the easy part, since you don’t have to opt for the same colour or brightness – which is what we’ll come to next.

 

Function

As we’ve already determined, there are many different types of lighting fixtures, that can be used for different purposes. The function that the light fitting fulfils will determine the brightness, and the hue of the bulb that you choose.

 

Brightness

Newer types of bulbs use different amounts of watts to produce the same amount of brightness – and there are differences between types. Historically, light bulb manufacturers used the number of watts that were required to produce the amount of light to illustrate the brightness of a bulb.

Today, bulbs are much more efficient, and to produce the same amount of light as an old style incandescent 60 watt bulb, an LED bulb needs just 10 watts, while a halogen bulb requires around 42 watts. The differences in watts required for the same amount of light is the reason that light bulb manufacturers no longer use the measurement of watts to describe the brightness of a light bulb. So rather than measure the amount of power required, manufacturers now use Lumens to describe the levels of brightness that the bulb will provide. The higher the number, the brighter the light provided by the bulb.

 

Warmth

When choosing your light bulbs, you’ll also need to consider whether you want a cool toned, or a warm toned bulb. The decision will depend on several factors:

  • What type of fixture you’re using the bulb in
  • The space the light is being used in
  • What activities the light will illuminate
  • The time of day the room, and the light will be used

For rooms that require lighting levels that are near daylight, and that aren’t being used close to bedtime, then a cooler toned bulb can be used – bright white, or slightly blue-toned, will help to mimic natural daylight. Where being alert is not as desirable, such as for bedside table lamps, then warmer, yellow toned bulbs are preferable.

The measurement of bulb warmth is measured in Kelvins. The warmth of candle light is measured at approximately 1,500 Kelvin, while normal daylight (depending on whether it is a sunny or cloudy day) is measured at between 5,000 and 7,000 Kelvin. The higher the number on the Kelvin scale, the colder the light provided will appear, and cooler toned bulbs often appear to be brighter than warmer toned bulbs of the same Lumen measurement.

 

kelvin colour temperature scale infographic

 

Choosing the bulb

Although watts are no longer used as a measurement of light bulb brightness, most bulb manufacturers will display both the Lumen measurement, and the equivalent in watts in an older style incandescent bulb, as well as the Kelvin measurement on the packaging. Not only that, but there will also usually be a description in words to describe the type of light – such as ‘warm white’. That means that when you’re in a store picking a light bulb, if you’re used to choosing bulbs based on watts, you’ll be able to see the numbers that you need, and the description will help if you’re not sure.

 

Format

Once you’ve decided on the colour, brightness and you know the fitting that you need, you can narrow down the shape that you want. There are an incredible array of different shaped bulbs, from traditional ‘bulb’ shapes, to candle, golf ball, pear shape, spiral and stick bulbs – and once you’ve established that you have the correct cap fitting (either screw or bayonet, for example) and the correct brightness, it is up to you. In many cases, if the bulb is hidden, the choice of bulb will be simply down to personal preference and it won’t matter. However, if your lighting fixture intentionally exposes the light bulb, then it may be better choose a style with a decorative filament, or that complements the design of the fixture.

 

Cost

While the general rule of buying the best quality you can afford definitely comes into play here – since a better quality bulb is likely to last longer too. The longer-term cost of running a bulb will also be relevant, especially if you are in your ‘forever home’. The initial cost of LED bulbs are higher than other types, but they are much more energy efficient, and can last for up to 25 years. Not only does this provide much more convenience – you won’t need to replace it as often – but the energy savings can add up dramatically. Savings can add up to more than £180 over the product’s lifetime, which makes it well worth the investment.  ­

 

Final thoughts

We’ve covered the basics of lighting in this post, and yet we’ve barely touched on design. Understanding the basics of lighting is important though, and can help to guide your decisions when you’re designing, and shopping for the room of your dreams. Our key takeaways:

  • Ensure you have a range of lighting in each room, with at least one light from each category of ambient, task and accent lighting
  • Be careful to measure before making a purchase – having lighting that is in proportion to the room, and that allows sufficient clearance is essential
  • Choosing the best bulb for the purpose should be done carefully, with the correct brightness and colour taken into consideration

Our range of lighting covers all the types of fixtures mentioned in this post, and we stock an extensive range of bulbs. If you are looking for a particular item, or need technical advice, please get in touch – our team of experts are happy to help.

 

charles author bio

Charles Barnett Managing Director

Charles started Lyco in 1995 with just 4 enthusiastic employees and has grown it considerably over the past 25 years. Charles is also the Managing Director of Lighting Direct and newly acquired Online Lighting. He now has a team of 50 lighting experts working on growing Lyco Group to be the UK leader in lighting for both businesses and homes. Away from the office he is a keen cyclist and is proud to have cycled 1017 miles from Lands End to John O’Groats to raise money for a new residential centre for adults with multiple learning difficulties.

Commercial & industrial lamps – pros & cons

Investment in lighting is important for any industrial or commercial premises. Practical benefits aside, the right choices will minimise running costs and strengthen profits. Linear fluorescent and HID (High Intensity Discharge) lights are the norm in this sector, though LED technology is gaining in popularity. This article looks at various commercial and industrial lamps and weighs up their pros and cons.

HID Lamps

HID lamps produce light by creating an electric arc between two electrodes in a gas-filled tube. They are a particularly powerful light source, used for car parks, gyms, factories, football stadiums, paths, roads, and warehouses. There are various types of HID lamp, as follows.

Metal Halide lamps last from 7,500 to 20,000 hours and are used in sports stadiums and car parks. They are also a good choice for warehouses and other high bay indoor purposes. The lamps produce a crisp white light and offer a good standard of colour rendering with typical CRI 60 to 70 scores. A choice of colour temperatures is possible, from warm white to daylight. With a luminous efficacy of between 80 and 120 lumens per watt, these lamps match the best LED or fluorescent products for energy efficiency.

Venture 250W Double Ended Metal Halide Bulb

A typical example of a metal halide lamp is the Venture 150W Double Ended Metal Halide, which has a cool 4200K colour temperature that’s ideal for work areas and sports activities.

The main disadvantages of metal halide lamps include light pollution, UV emission if their outer glass breaks, and use of mercury and other heavy metals.

Ceramic Metal Halide (CMH) lamps are also called ceramic discharge metal-halide lamps (CDM). The main difference between them and regular quartz metal halide lamps is that they allow a higher arc tube temperature, resulting in improved colour rendering and stability. For this reason, CDM lamps are often used in colour-critical applications such as retail display lighting, architectural lighting, or film and television.

The natural deluxe version of the G.E. 70W Single-Ended Ceramic Metal Halide boasts a CRI 90 score, which puts it ahead of most current LED products in terms of colour.

SON-E lamps are elliptically shaped, high-pressure sodium lamps. They are used in street lighting and general floodlighting. One of the main advantages of these lamps is their energy efficiency, which is shown by a luminous efficacy ranging from 65 to 140 lumens per watt. The higher end of that scale is unsurpassed by most light sources. Lifespan is also impressive with average expectancy of 15,000 to 50,000 hours. Colour temperature in these lamps is always warm.

SON lamps work with ignitors, which are either in the lamp itself (internal) or in the fitting (external). The 70w SON-E uses an internal ignitor and boasts a 12,000-hour lifespan and luminosity of 5,800 lumens.400W Son-E Bulb with Giant Screw Cap Fitting

 

On the down-side SON lamps offer poor colour rendering. A CRI 20 to CRI 30 score reflects this, which is unusable in any setting where colour recognition is important.

SON-T lamps are tubular high-pressure sodium lamps, with the same advantages and disadvantages as SON-E varieties (above).

White-Lux SON lamps are a metal halide lamp designed to work in a standard SON fitting. The main benefit is a more natural light with a cooler colour temperature and greatly improved colour rendering. Possible uses for this lamp are identical to those listed under metal halide, including sports stadiums and halls, car parks, and warehouses. This is a fine choice for anyone who wants to upgrade light quality in an existing SON fitting without having to change either the fitting or ballast.

Mercury vapour lamps are used in applications such as warehouses, car parks, stadia and other large-scale industrial buildings. They are a type of gas discharge lamp that uses an electric arc through vaporised mercury to emit light. A white phosphor coating is often used on the outer lamp to generate an intense white light.

The main drawbacks of high-pressure mercury vapour lamps are their slow 4-7 minute warm-up time, middling energy efficiency (about 50 lumens per watt), and inferior colour rendering compared to metal halide lamps.

Dual SON & Mercury lamps are dual metal halide lamps that can be used in either SON or mercury fittings for superior performance. They give a whiter, crisper light with improved colour rendering, and this is achievable without the cost of installing new light fittings or control gear. Suitable applications include factories, retail environments and sports halls.

White SON [SDW-T] lamps run at a higher pressure and temperature than regular SON lamps to achieve a superior standard of colour rendering. Manufactured by Philips, they usually carry a minimum CRI 80 score, which extends their suitability to applications such as downlighting, display lighting, and café or restaurant lighting.

There are disadvantages with White SON lamps, however, including high upfront cost and reduced energy efficiency. Our Philips models have a luminous efficacy of about 50 lumens per watt, which is less than half that of some HID lamps and is roughly equal to low-end LED or fluorescent lighting.

Philips 18W SOX lamp with a bayonet cap fitting

SOX (low-pressure sodium) lamps are gas discharge lamps that use sodium and neon gas to produce yellow light. These are the most energy-efficient of all artificial light sources, with typical luminous efficacies of between 100 and 180 lumens per watt. They are ideal for applications such as airports, harbours, foundries, orientation lighting, quarries, railway marshalling yards and crossings, rolling mills, security, and street lighting.

The main downside of a SOX lamp is its monochromatic light, which makes it impossible to discern colour in the absence of any other light source. For that reason, it’s a poor choice of lamp in any setting with colour safety markings or where crime prevention is needed.

LED

The LED Light Panel is one of our most popular dedicated commercial LED light fittings

LED commercial and industrial lighting often comes in the form of dedicated LED fittings, which are so long-lived that they do not take replacement bulbs. The whole fitting is replaced at the end of its useful life. LED lighting is naturally directional and thus easy to control. For that reason, dedicated LED fittings are uncommonly efficient in delivering light and less wasteful than other sources.

Disadvantages of LED include greater upfront cost and lower energy efficiency at source than some rival products (the best LED lighting cannot match the lumens per watt performance of sodium lamps). On average, colour rendering is likely to be better in a ceramic metal halide lamp; most LED products have an approximate CRI 80 score.

Linear Fluorescent Lamps

Fluorescent tubes have long been popular in industrial and commercial environments as a cheap source of diffuse light. Lyco stocks a variety of fluorescent batten fittings to house them, some of which are usable outdoors. The main disadvantage of fluorescent lamps against HID lamps is that they produce less light, so you’ll theoretically need more fittings to provide the same coverage. They are also adversely affected by hot or cold temperatures, resulting in lower light levels. Linear fluorescent lighting is ideal for corridors, tunnels, and aisles.

Need more guidance?

Lyco has many years of experience in serving all types of trades and industries. Please feel free to contact our sales team for advice on lighting any premises.

Feel free to browse our full range of commercial bulbs.

Alternatively, for more lighting guidance take a look at our advice section.

andrew-author-bio

Andrew Evangelidis Head of Buying

Andrew is an experienced buying professional who takes an entrepreneurial approach to identify new lighting solutions and ensure Lyco have first-to-market ranges for our customers. Having previously worked for well known brands such as Wickes, Carphone Warehouse and Toys R Us, Andrew has now turned his hand to sourcing commercial lighting and ensure our customers receive top brand quality products at marketing leading prices. He manages a team of commercial and decorative buyers who travel the world finding new products that our customers don’t even know they need yet.

Commercial lighting – the basics explained

Ivela High Bay Light - Translucent/Black

Every designer and electrician whose work brings them into contact with commercial lighting will be well aware of the vast range of suitable fittings and equipment available to them. They will also be conscious of the importance of choosing the right commercial lighting fittings for the project in hand. Similarly proprietors of businesses commissioning such work will have their own quite clear ideas as to what they need and expect from their new commercial lighting.

Lighting contractors will naturally have kept up to date with the exciting developments seen in recent times in lighting systems. Their customers may not however so it may be helpful to highlight some of the benefits they bring to users of commercial lighting.

Better lighting, better economy

Low energy lighting has been with us for some time now with its benefits of lower consumption of electricity and longer bulb life leading to improved economy in use. These benefits were achieved by the use of compact fluorescent bulbs but they were frequently criticised for being bulky, unattractive and producing light of lower intensity than expected. These lights still suit many situations but awareness of the other options that have become available more recently is essential if the right decisions are to be made.

With the advent of energy-saving halogen bulbs, metal halide lights and LED systems, light of greater brightness and intensity than was ever available from traditional incandescent bulbs and fluorescent tubes comes with dramatically improved economy. Every business needs to keep costs to a minimum and energy bills can account for a considerable proportion of overall operating costs. The high energy efficiency of these new forms of commercial lighting can bring about a significant improvement in the bottom line.

Examples

To show you exactly what we mean we have selected lighting examples from four broad categories of commercial lighting (retail display, high bay lighting, low bay lighting and including flush fittings) that suit all locations. We recommend suitable fittings for each situation.

Retail Display

The lighting here needs to clearly illuminate all areas of the sales area to enable customers to see everything clearly, move around safely and to deter thieves. The goods on display should be highlighted so that they are shown off to best advantage.

Metal halide lighting is perfect for this. Its bulb produces up to 115 lumens per Watt of electricity consumed compared to 35 for a traditional incandescent bulb. It lasts 20 times as long too, so economy comes as standard. These lights can light up a very large area or they can provide high intensity light on a small area.

A fine example is the Zeta Metal Halide Display Light from Robus in cast aluminium. You get a lovely crisp white light which really brings the display to life and showcases the products to best advantage.

Also ideal for situations such as shops are flush fitting. Flush mounted on either ceilings or walls they will illuminate large areas. These lamps use low energy bulbs for economy. For ultimate economy, LED versions are available.

High Bay Lighting

Here we are looking at lighting installed at heights of 20 feet (6 metres) or more above floor level, which may be in a warehouse, a sports hall, or maybe a large restaurant, even a pub or large retail sales area.

Recommended light fittings for these installations would include the 100w LED Linear High Bay Light. These high efficiency lights with their excellent economy are equally at home in High Bay situations where they are extremely effective.

Also extremely versatile and particularly suited to high bay installations are Solid Slim 200w LED Circular High Bay Lights. These are IP65 rated so they can be used where dry conditions cannot be guaranteed.

Low Bay Lighting

LowBayis required in situations where the lights are to be installed 3 to 7 metres or about 10 to 23 feet above floor level. Dextra’s Low Bay Lights – Metal Halide 250W are designed for just this purpose.  These lights provide all the benefits of the latest metal halide technology as highlighted in the high bay lighting section plus a hinged gear tray which makes them quick and simple to both install and later maintain. The time thus saved represents a further saving in overall cost. Their robust construction makes them ideal for commercial lighting purposes particularly in factories, hangars, warehouses and loading bays.

Flush fittings like the Carina Flush Fitting LED White provide an excellent alternative in a low bay situation. The more limited the headroom available the greater the benefit of using flush fittings. We take a look at flush fitting lights next.

Flush Fitting Lights

Flush fitting lights are the maids-of-all-work of commercial lighting. We have two examples which show you just how versatile these lights are. Carina Flush Fitting LED White is the LED version of the Carina flush fitting mentioned under retail display. It provides all the advantages of flush fitting in that it protrudes very little from the surface it’s mounted on and can be wall mounted or ceiling. It is IP65 Rated which makes it ideal for hotel bathrooms, shower- cubicles and pub toilets or outdoors exposed to the elements.

On top of all that it is an LED light. LEDs produce beautiful white light, with the lowest of all energy consumption and the LED arrays outlast every other type of light source except the sun! Installing LED lighting is one of the few things a business can do which reduces costs whilst actually enhancing quality.

The other example is actually another version of the same light. The Carina LED Flush with Microwave Sensor – White. Here you get all the benefits already described plus the microwave sensor.  The light can be mounted outdoors to light up walkways, steps or other areas either for safety or convenience. It can also be a security light.

Its microwave sensor detects movement and turns the light on only when needed. It can be adjusted to become active only when the ambient light falls below a pre-set level and its sensitivity can be varied between 1 and 10 metres so that it only detects movement in the relevant area. The time the light remains on when activated can be pre-set to between 10 seconds up to 30 minutes.

Indoors these are the ideal lights for rooms or passageways that are not in constant use. As someone enters the area the lights obligingly turn on. One extremely useful benefit of the microwave sensor when compared to the PIR type of movement detector is that the microwave sensor can see through doors! One advantage that gives is that when someone approaches a closed room the sensor inside the room detects their arrival outside the door and turns on the light ready for when they enter the room.

All LED lights cost very little to run. These only come on when needed and remain turned off and costing nothing the rest of the time.

Update to save

It’s not only new business premises or those undergoing extensive refurbishments that can benefit from these developments in commercial lighting. All businesses need to be alert to changes that can reduce trading costs and in many cases the cost of updating their lighting installations could be repaid many times over in the long term by the savings in running expenses.

Take a look at our full range of Commercial Lighting

For more advice, inspiration and news take a look at our Lighting Advice section.

 

Charles Barnett Managing Director

Charles started Lyco in 1995 with just 4 enthusiastic employees and has grown it considerably over the past 25 years. Charles is also the Managing Director of Lighting Direct and newly acquired Online Lighting. He now has a team of 50 lighting experts working on growing Lyco Group to be the UK leader in lighting for both businesses and homes. Away from the office he is a keen cyclist and is proud to have cycled 1017 miles from Lands End to John O’Groats to raise money for a new residential centre for adults with multiple learning difficulties.