The Three Different Types of Lighting: An In-Depth Guide
Posted on April 28 2017
For lighting applications, professionals generally categorized them into three groups: general, task, and accent lighting. The different types can determine many factors from choices of bulbs, placements, fixture designs, wattage requirements, and many others. Therefore, understanding the difference between three types is really important.
In this article. we will do an in-depth discussion for each type, and how their differences might affect your applications as well as purchase decisions. Without further ado, we will begin with the first type:
General Lighting also often called ambient lighting, because they provide 'ambiance' by illuminating an area thoroughly. General lighting is the most common of the three types and can come in many different types of fixtures, which we will touch briefly below. They are also often referred as mood lighting because it will set up the overall mood of a room. Studies suggested that correct applications of general lighting can reduce stress because general lighting can allow your pupil to dilate by softly illuminating the curves of your face.
On the other hand, over-illumination can cause tiredness and anxiety, not to mention a waste of energy. Hence, for general lighting, soft level of light is commonly desired. For general lighting, your aim is to create illumination as 'natural' as possible. Here are a few things you might want to consider regarding General Lighting:
Color Rendering Index
The common misconceptions is that Color Rendering Index is similar to Color Temperature. However, they are actually two different things. Color Temperature is a measure of the color pallet of the light source, which are caused by the produced heat (hence, 'temperature'). Color Temperature is measured in Kelvin. Color Rendering Index, on the other hand, is the ability to reproduce color in comparison to the natural (or ideal) light source. Natural light (i.e. sunlight) have a CRL of 100. Now, since the aim of general lighting is to produce illumination as natural as possible, CRI above 80 is desired, with 85 to 95 being the ideal one.
First things first, all color temperatures can have CRI above 80, as we have mentioned those two are on separate things. Regarding color temperature for ambient lighting, there are generally two different approaches:
- Using uniformed color temperature for the whole household
- Using different color temperatures for different rooms
Both are perfectly valid, as they are a matter of taste and preference. However, there are some things you might want to consider:
Blue tint from higher color temperatures (6000 Kelvin and above/cool white) can increase concentration. On the other hand, it can cause sleep difficulty by suppressing melatonin production. Thus, cool white bulbs are better suited for high-activity rooms such as entertainment room or living room and should be avoided on bedrooms.
On the other hand, warm lighting (below 3000 Kelvin) can be used to stimulate relaxation
Experiment with color temperatures to create the perfect atmosphere for your household or office.
Ceiling height can dictate your brightness choice. The general rule of thumb for ambient lighting is that the lower the ceiling, the softer the brightness should be. Refer to other factors above and blow to adjust the proper brightness depending on your ceiling height, and depending on the intended room usage.
Illumination Levels are commonly expressed in foot candles (fc), while some regions use lux (1 lux= 0.092903 fc). For a general household application, the average of 3 fc is sufficient. For office spaces with simple tasks, you can aim for a 10 fc average. Read further below for task lighting applications to understand more about applying illumination levels.
Smart Control: Dimmer/Daylight Sensor/Smart Home Control
In this modern day of smart home technologies, we are graced with many control methods that can not only save energy but can also bring out better aesthetic and functional values of your general lighting. Consider whether you will need a simple dimmer for a certain room, or a full-fledged smart home control system with multiple sensors for others.
Examples for general lighting applications can be so diverse. In fact, any overhead lighting most likely can be categorized as general lighting application. Here are some of the most common application examples, along with some unique ones
Probably the oldest form of general lighting fixtures, chandeliers originally used with candles. Chandelier fixtures are your go-to solution if you want a classic look on your house, and are better applied to high ceilings. Besides their obvious decorative benefit, chandeliers can help bring more diffused illumination with their designs, as well as the use of crystal/glass reflectors. Play around with height when you are using chandelier fixtures. For example, you can place it a bit lower with softer brightness choice in areas where people will not walk near.
In many ways, pendants are quite similar to chandelier fixtures. We can even arguably say that pendants are the modern equivalent to chandeliers with very few exceptions. Thus, if you are looking for a more modern look with a high ceiling, you can opt for pendant fixtures.
Wall sconces and other in-wall fixtures are often integrated with architectures and can be very effective and versatile general lighting methods. Use wall fixtures sparingly, as they can lead to over-illumination.
A fairly new and modern type of general lighting. Very versatile and can be used with almost all kinds of ceilings.
Also a fairly modern general lighting fixtures. Very versatile and can bring out excellent effects. The downside is, they will need to be integrated into your architecture, so it's fairly hard to install without a major overhaul.
While general lighting is intended to produce a diffuse, overall illumination for atmosphere and ambiance, task lighting, as the name suggests are intended to help you perform specific tasks. Reading lights for, well, reading, kitchen lights for food preparation and cooking, writing lights, and many other specific lights can be categorized as task lighting.
The first thing in you should keep in mind is the objective of the task lighting itself, which is to illuminate a specific function or area to allow the user to accomplish some task. With that in mind, obviously, you will generally need a higher level of brightness compared to general lighting.
As with general lighting, there are some principles and considerations you might want to consider for task lighting applications:
Color Rendering Index
Color Rendering Index will be especially important for some, if not most forms of task lighting applications. Humans are known to perform better with natural light, and some task lighting applications, such as photography lights will require a natural color reproduction. Aim for CRI above 85, with 95 and above being the ideal ones.
The same principle applies here: blue tint will help you focus better on critical tasks, but can cause tiredness with over-exposure. For demanding tasks such as medical or lab works, cool white lighting with high illumination levels (more on this below) is preferred. For activities that are aimed for entertainment or relaxation (i.e. reading), warmer color temperatures are preferred. There is, of course, no clear rules for color temperature applications, and you can always be creative and experiment.
It is also a great idea to differentiate the color temperature of the task lighting with the surrounding general lighting, both for aesthetic and performance. Humans tend to concentrate more when there are 'accents' to differentiate their relaxed activities and intended focused activities.
As with Color Rendering Index (CRI), illumination levels will also be more important for task lighting applications, compared to the respective general lighting. Although as mentioned, task lighting will need an overall higher brightness, it does not mean that you should make it as bright as possible. Because a lot of tasks and activities are done on screen nowadays (TV, PC monitor, smartphone) Some tasks will require a comfortable 'contrast' level between the task lighting and the screen illumination.
Over-illumination from the task lighting can cause screen glaring and ultimately, visual discomfort. Thus, it is wise to consider a balanced brightness level between the overhead task lighting and backlit screen. Again, there will be no clear set of rules, and you can always be creative. However, here are some of the key principles to help your ideas:
- For simple office spaces, 10 fc (foot candles) is adequate
- For areas with short visits, such as receptionists or similar functions, try 5 fc of illumination
- For most household applications (kitchen, entertainment rooms), 30 fc is adequate
- For working spaces with critical tasks, the illumination level will increase as the contrast goes higher and the objects go smaller.
For example, large office spaces with heavy computer usage (i.e. big graphic design office) will only need 30 fc. On the other hand, medical laboratory with a lot of screens and small objects to tinker with might need above 300 fc, sometimes reaching 1,000 fc.
Task Lighting tend to be more diverse in placements compared to general and accent lighting because their placements will be determined by several factors, including the intended task. As a general rule of thumb, placing a softer task lighting closer to the task object is preferable, and less tiresome to the eye, compared to placing high-intensity lighting with considerable distance. That is, of course, excepting if it is intentional, either for aesthetic or functional purpose.
To avoid screen glaring, however, using low-illumination task lighting at a closer range to the screen will always do the trick.
Common Types of Task Lighting
There is also no limits for task lighting applications, and you can always be creative. However, task lighting can generally divide into these several types. Use this classification as a consideration for your application ideas:
Fixed Task Lighting
A static, non-movable task lighting for a specific task. Kitchen lighting including under-cabinet lighting belongs to this type. Static table lamp mounted on a reading table can also belong to this category.
Localized Lighting (Ambient+Task Lighting Hybrid)
Localized lighting commonly used a fixture that can provide both ambient light and task light, or achieve both purposes with a single light source. Most often, this type will come as an overhead lighting and is common in office settings with recessed lights mounted up over the workplace. They can also be desk-mounted or wall-mounted, or even free-standing.
Adjustable Task Lighting
As the name suggests, this type can be freely adjusted, and the main focus is versatility. A freely adjustable lamp can help for glare control, as well as to adjust contrast which can be important for older users. The most common of this type are the swing-arm light fixture with adjustable neck. They can come as wall sconces, free-standing desk lamps, and many others.
Magnifying Task Lights
For critical tasks, some task lighting can come with built-in magnifying glass. This niche type might be limited in applications, but it can be highly beneficial for the right tasks. A common example you might have seen is dentist's light. For household usage, this type can be useful for certain hobbies like sewing or model building, as well as several niche tasks.
Asymmetric Task Light
Another niche type, this task lighting type is distributed evenly across the task, instead of being focused directly on the task itself. Useful for larger desks, and can prevent glaring and reflection to colleagues.
Common Application Examples
Here are some application examples you can use as inspirations.
Floor Lamps and Desk Lamp
The most common form of task lighting. Commonly used on bedside table, coffe table, reading desk, and anywhere where extra lighting is necessary for reading or working.
Swing Arm Lamps
Swing arm lamps are built with the emphasis on flexibility. They are also often portable, so they are very versatile to use for many non-critical tasks.
Under Cabinet Lights
Under cabinet lights are almost a must-have in any modern kitchen nowadays. Very functional to aid cooking and food preparation, yet is also an important element of kitchen aesthetics.
Vanity lights are commonly found in bathrooms and dressing rooms. Can also be applied for workstations, garages, and other niche tasks.
Pendant and Track Lights
Although pendant and track lights are generally applications for ambient lighting, they are also great fixtures for task lighting applications. Very versatile regarding placement, as they can fit a lot of areas. Track lights can fit more space than pendants, so they are ideal for offices, kitchen islands, and even children studies.
Accent lighting might differ with the other two types because the main objective of them is often pure aesthetic. Accent lighting, as the name suggests, is intended to build a visual accent, creating a point of interest for the viewer. Common applications of accent lighting are to accentuate houseplants, sculptures, painting, and other decorations. You can also use accent lighting to emphasize architectural textures, outdoor landscaping, and many other points of interest.
As with the other two types, there will be a set of principles and considerations you can use for accent lighting applications, they are:
Color Rendering Index
One thing to remember regarding CRI for accent lighting is that the objective is to look different compared to the surrounding ambient lights. Thus, you have more freedom compared to general lighting or task lighting applications. You can use same CRIs between the ambient lighting and accent lighting, or you can use completely different ones for the intended 'accent'.
It is often a good idea to keep a natural CRI as close to 100 as possible because they are generally more pleasant to the eye. However, as mentioned, you have more freedom here compared to the other two.
The same principle applies regarding color temperature. The easiest way to create the intended accent is to use a significantly different color temperature compared to the ambient lighting. However, that should not always be the case. You can also play along with different brightness or illumination level to create visual interest.
A good principle is to use a color temperature that can bring out the color of the intended object. For example, green houseplants tend to do better with warmer white, or even yellowish color temperature (although that is not always the case). On the other hand, paintings might do better with natural white or even cool white to bring out the vividness of the colors. Therefore, you have some form of freedom, but it should be determined by the object of interest.
Generally, you will need an illumination level higher than the surrounding ambient lights, without being over-illuminated. A small difference of 3 to 5 fc is enough to create the intended accent, so you will not have to overdo it. Instead of using over-illuminated accent light, try lowering the illumination level of the surrounding general light. Again, you have a bit of a freedom here, and you definitely experiment with your own creativity.
The required illumination level will also depend on the size of the object of interest. The larger the object, the higher the illumination level will be needed. The golden rule for accent lighting is that to be effective, they require at least three times at much light compared to the surrounding general lights.
Because accent lighting have more aesthetic purpose compared to the other two types, fixture selection will be more important. Because this is a matter of aesthetics and preferences, there will be no clear rules. However, as with the previous principles, you can generally let the object dictate the proper fixture choices. For example, using overly modern fixtures might not be suited for houseplants or classic sculptures (although when done properly, can bring out great accent). There is no limit to this, only limited by your own creativity.
Diffusion vs Directional
LEDs are directional in nature (except with certain fixtures or reflectors), while incandescent and fluorescent are more diffused. These facts can come to great effects when you are designing accent lighting applications. Some focal point objects are better of with more diffused lighting, while others are better with directional lights.
For example, outdoor landscapes are generally better off with more directed lights. One thing to remember is that directional lights are more energy effective, not only because it commonly comes from LEDs, but also because you will need more diffused lights to illuminate a certain object.
Common Application Examples
Remember, the objective of accent lighting is to create a point of interest, and your application must emphasize that point. Here are some ideas to achieve that objective:
Variations of wall lights are commonly used to design accent lighting. In fact, it is probably the most common form of accent lighting nowadays. One benefit of using wall fixtures are the size flexibility, only limited by the wall space. Great for lighting paintings or even wall architecture.
Recessed lighting are often used for accent lighting applications, mainly for wall washing. Often placed at the base of a wall to illuminate paintings, windows, or even wall textures. Spot lighting can also be used for a more direct effect.
Easiest way to see an example of accent lighting is, arguably, the landscape applications.There are many types of landscape lighting available, check out our previous guide for landscape lighting here.