In this guide we'll discuss all the attributes involved in how projectors work. There are many interleaved aspects of projector design that affect the end image; understanding these facets and the impact they have will ensure you make the right decision when purchasing a projector.
The best place to start when researching projectors is what you're going to use it for.
For office use a projector enables you to deliver presentations and videos on much larger screens than is possible using a TV or monitor. This is particularly useful in meetings and conferences, as text and tables will be more readable to a larger number of people.
For education use a projector enables you to deliver presentations and videos on much larger screens than is possible using a TV or monitor. This is particularly useful in large classrooms as text and tables will be more readable to a larger number of people.
A projector delivers a cinema-like experience in the comfort of your home, providing a much larger image than is possible on a TV. While you will need either a projector screen or flat white wall, it's the best way to watch films and sport.
A projector can make gaming even more epic, providing a much larger image than is possible on a monitor. While you will need either a projector screen or flat white wall, it's great for split-screen gaming and specialist games such as golf simulators.
The table below shows four popular use cases, indicating with a score from 1 (least) to 5 (most) of what is important to consider.
| TYPE OF USE | Size of Projected Image | Brightness of Image | Likelihood of Extended Use | Minimal Noise | Recommended Projector (entry-level) | Recommended Projector (high-end) |
|---|---|---|---|---|---|---|
| Office | 3 | 4 | 2 | 3 | LCD FullHD | DLP 4K |
| Education | 5 | 4 | 3 | 2 | LCD FullHD | DLP 4K |
| TV & Home Cinema | 4 | 5 | 5 | 5 | DLP 4K | Laser LCoS 4K |
| Gaming | 4 | 5 | 5 | 5 | LED DLP FullHD | Laser DLP 4K |
As with types of display technology this isn't the whole picture, so we'd recommend you explore the tabs below to understand more about the different features that define how the image will appear.
Image size is determined by the distance between the projector and the screen. Common projection sizes used in home or office environments range from 100in to 200in, but can go as large as 300in. The correct size for any given scenario will also depend on the usage - for example a 200in image size will work well for a classroom of 50 students to view a presentation.
However, this same size would be impractical for gaming or home cinema, as you would need to be so far away as to not have to move your head to appreciate all the image that you would miss finer details.
Throw ratio is the measurement of how large an image a projector can create, being determined by ‘Throw Ratio = Throw Distance / Image Width'. For example, a projector with a throw ratio of 2.0 needs to be two feet away for every foot of image width. Using this same example, if the projector was five feet away from the screen the image size would be 10 feet. This diagram gives an indication of screen size optimal for the throw distance you have available.
If you have a smaller space then projectors with a smaller throw ratio are available (1.0 to 1.5) - these are capable of projecting a large image onto a much closer screen, but are usually more expensive.
Resolution is the number of pixels (the tiny dots) that make up the image - it is shown as a number for image length and a number of image height. The most common projector resolutions are shown below, along with a recommended screen size required to result in a good image.
It is also worth mentioning that although 4K / UHD projectors are reducing in price, they do require a very high-end graphics card within the PC to power when gaming.
| Resolution | Name | Size Recommended |
|---|---|---|
| 1920 x 1080 | FullHD | Up to 100in |
| 1920 x 1200 | WUXGA | Up to 100in |
| 3840 x 2160 | 4K / UltraHD / UHD | 100in + |
Aspect ratio is the difference between the image width and height, and gives a representation of the image shape. Most projectors have a 16:9 aspect ratio, but can support the older 4:3 standard used by legacy content.
Projectors use one of three main technologies - Digital Light Processing (DLP), Liquid Crystal Display (LCD) or Liquid-Crystal on Silicon (LCoS). Each technology offers its own distinct advantages and disadvantages, depending on the type of content you want your projector to display and the setup of your room.
DLP (Digital Light Processing) projectors contain an array of microscopic mirrors that tilt toward or away from the light source to create a light or dark pixel on the screen. They are available in either single-chip or three-chip versions.
Single-chip DLP projectors use one panel to form the image so the resultant image is very sharp, but only black and white. A wheel that rotates between the three primary colours is used to enhance the monochrome image. Some people can see this movement as a rainbow effect, so its worth viewing a single-chip DLP projector before purchase just in case you suffer from these visual artefacts.
Three-chip projectors use a panel for each colour instead of a colour wheel, however getting all three panels in perfect alignment is harder and therefore requires a more complex and expensive design. Three-chip DLP projectors are usually the type used in cinemas, as they are capable of producing bigger, brighter images, with resolutions up to 4K, high colour gamuts.
DLP also excels at 3D projection, as the mirrors turn completely on or off, 3D is free of the faint double images that can sometimes be produced by other technologies.
The instant on/off ability also makes three-chip DLP projectors a good choice for sports with fast action and gaming because of their fast response and lower lag times.
LCD (Liquid Crystal Display) projectors shine a light through a single LCD panel and employ a colour wheel in a similar way to a single-chip DLP projector.
They aren't as bright as DLP projectors, but are better at producing deeper blacks than DLP projectors.
Motion is not as sharp and fast as a DLP projector can produce, and 3D images can be less accurate too suffering from faint double images.
On the plus side as LCD projection is an older technology, these are the most affordable projectors.
LCoS (Liquid Crystal on Silicon), like LCD, shines light through a panel to create an image. Unlike LCD projectors the light from a LCoS projector reflects off three individual LCoS colour panels, which are then combined to produce the image.
By reflecting the light off the panel instead of shining light through it, LCoS projectors offer the darkest black levels and contrast ratios of any technology. Better black levels make the film more immersive when viewed in a dark room. Plus, the letterbox bars on CinemaScope-format movies disappear and shadows look much better. Darker blacks also help increase the contrast ratio, which gives the image more pop.
Because LCoS projectors usually offer lower levels of light output, they often don't work well when paired with very large screens. They also exhibit more image blurring on fast-moving images than DLP and some LCD projectors. For film, this isn't an issue, but it makes them problematic if watching sports, 3D content or gaming.
Additionally, LCoS projectors usually cannot offer the same brightness levels of DLP and LCD projectors - which makes these two types of projectors ideal for rooms where there is a high degree of ambient light, or if you like to watch TV with the lights on.
| Feature | DLP (Digital Light Processing) | LCD (Liquid Crystal Display) | LCoS (Liquid Crystal on Silicon) |
|---|---|---|---|
| Technology | Reflective (Micromirrors) | Transmissive (Liquid Crystal) | Reflective (Liquid Crystal) |
| Best For | Gaming, TV & Cinema | Value | TV & Home cinema |
| Contrast / Blacks | Moderate for 1-chip Excellent for 3-chip |
Moderate | Excellent |
| Colour Accuracy | Good, but some people see “rainbow artefacts” | Excellent | Outstanding |
| Motion Handling | Low motion blur | Moderate motion blur | Variable (Some motion blur on rapidly moving images) |
| Suitability for bright rooms | √√ | √√ | √ |
| Suitability for dark rooms | √√ | √√ | √√√ |
| Cost | ££ | £ | £££ |
All these three types of projectors use a high-powered light source, most commonly a lamp, LED or laser. Lamps are the most common type, being low cost and easily replaceable. However, they have a relatively limited life, typically between 4,000 and 15,000 hours depending on the brightness profile. It's also worth noting the lamps get dimmer over time, so although a lamp may have a 4,000 hour rating, after 2,000 it may only really work in a darkened room.
LEDs are commonly used in portable and smaller projectors due to their lower power consumption and lower operating temperature. They typically are rated for around 20,000 hours and do not dim over time.
At the high-end, are laser light sources, which are typically rated for as many as 30,000 hours and like LEDs do not dim over time. Additionally, lasers are so fast they can turn off and on almost instantly to produce darker blacks than a traditional lamp can.
| Light Source | LAMP | LED | LASER |
|---|---|---|---|
| Brightness | High (for bright environments) | Medium (suitable for small environments) | High (suitable for daytime / living room) |
| Useful Life | 2,000-5,000 hours | 20,000-30,000 hours | 20,000 hours |
| Color Expression | Normal (cold or yellowish) | Good (bright and soft) | Excellent (wide color gamut and high contrast) |
| Maintenance Costs | Bulb replacement required | Almost zero maintenance | Very low |
| Startup Time | Slow (warm up/cool down) | Instant On/Off | Instant On/Off |
| Best For | Occasional Use / Budget | Portability / Small office | Home cinema / Large venue |
| Price | £ | ££ | ££££ |
After deciding on image size, aspect ratio and how you want your image created, there are a few other factors that determine the quality and sharpness of an image displayed. We'll start with a quick comparison of which ones are most important depending on what you'll be using the projector for. The table rates these facets 1 to 5 in degree of importance for various use cases.
| TYPE OF USE | Creation of Image | Light Source | Brightness | Colour Gamut | Refresh Rate |
|---|---|---|---|---|---|
| Office | 1 | 3 | 3 | 3 | 1 |
| Education | 3 | 3 | 5 | 3 | 3 |
| TV & Home Cinema | 5 | 4 | 5 | 5 | 4 |
| Gaming | 4 | 4 | 5 | 5 | 5 |
As before, further knowledge of each factor is advisable to ensure you make the correct decision when choosing your projector. Explore the tabs below for more information.
Expressed in lumens, brightness is important when selecting a projector. Only with appropriate lumens for the throw distance and ambient lighting can the projector produce clear images with true colours. If you need ambient lighting when using the projector, then a model with higher lumens will produce better results.
For example, if you'd like to watch films using a projector on a 100in screen in a darkened room around 2,000 lumens of brightness is ideal. If you need to turn on ambient lighting or if there are bright light sources in the room, a projector with 3,000 lumens or more will be required to display clear images. If you intend to use a projector outside you should consider nothing less than 5,000 lumens as a starting point.
It's also worth mentioning that you may see ‘ANSI Lumens' or ‘LED Lumens' when looking at projector specifications. ANSI stands for the American National Standards Institute, which operates a strict, standardised measure of projector brightness that allows direct comparison of models.
LED lumens on the other hand, measure the raw light source, often resulting in higher, sometimes inflated, numbers that don't account for light lost through lenses. It is always better to use the ANSI number for accurate comparison, however if only LED lumens are listed then divide by 2.4x to get an ANSI lumens equivalent.
Colour gamut is the range of colours a display can show – the wider the colour gamut, the more colours it can reproduce. In Hollywood film studios for example, Rec.709 and DCI-P3 are the standards for cinema-quality colours, so you should look for projectors that come closest to these standards. In addition to meeting colour standards, the projector should also have low Delta E (colour difference) values. The light source selection also plays a large part in colour gamut range - LED and laser sources offering far wider colour capabilities, but in projectors that employ a colour wheel, there'll be options including RGB, RGBW, RGBCMY, RGBCWY and RGBRGB. High-end DLP home cinema projectors typically feature six-segment RGBRGB colour wheels so this is the specification to look out for.
A High Dynamic Range (HDR) projector has the ability to display a broader spectrum of colours and contrasts. Basically, this means that an HDR projector more realistically displays nuances and colour tones, and shows more detail when it comes to light and dark. In order to display HDR image material, both the projector and the content need to be suitable for HDR. HDR content tells a projector exactly which colour and black levels are best for the most realistic display. Content that's suitable for HDR has this colour information embedded in it, so a game or video can easily use it provided you have an HDR certified projector.
Contrast ratio is the ratio between how bright your projector's white image is compared to its black image. Although a higher contrast ratio is necessary for displaying finer details, it's worth noting that your projector should be bright enough to deal with ambient light so that the contrast ratio can end up visible and clear. Only a small amount of ambient light from fluorescent or LED lights as well as daylight from windows can render the contrast and brightness of your projector moot. Whether your projector has a ratio of 10000:1 or 1000:1 contrast, it won't matter if you can't see it in action due to ambient light making your projection fainter than normal.
The refresh rate is the frequency at which the projector redraws the image and is measured in hertz (Hz). A faster rate of refresh (higher Hz value) will make for a much smoother image, so is particularly important when viewing rapidly moving content such as sports, films or games. Entry level projectors typically have a refresh rate of 60Hz, whereas 120Hz is common now in mid-range models, whereas high-end projectors may have rates up to 240Hz. It is worth mentioning that if you are connecting your projector to a PC for gaming, the resulting image is also affected by the frames-per-second (fps) delivered by the graphics card (GPU). If the graphics card can only deliver 60fps and your projector is 120Hz rated, you'll only be using half its capability. Transversely if you have a 120fps GPU, but only a 60Hz projector you'll only see the first 60 frames that the GPU is sending to the projector.
Response time or Input Lag is the time it takes your projector to process the video signal from the source and is given in terms of milliseconds (ms). Response time isn't really a factor for most projector uses but does have significant impact when it comes to gaming. Although a 50ms input lag is fine for most uses, gaming benefits from a much lower rate and there are projectors on the market now that deliver 16ms or lower.
All the attributes we've discussed so far ultimately have an impact on the resultant size of the projector and the noise it generates. If the projector is for a large classroom, size may not be an issue and noise will have minimal impact too, however if it is for home cinema use a compact model may be preferred and low noise is essential. The size of any projector is largely determined by the light source and the fans required to cool it. Naturally, the fan will generate noise as will the movement of the colour wheel. The table below highlights the difference in projector types and the impact this is likely to have on its size and the noise it produces.
| Lamp | LED | Laser | |
|---|---|---|---|
| Brightness | 2000+ ANSI lumens | Up to 2000 ANSI lumens | 3500+ ANSI lumens |
| Noise | Medium | Low | High |
| Size | Medium | Compact | Large |
| Weight | Medium | Light | Heavy |
| Cost | £ | ££ | £££ |
For our large classroom scenario a Laser projector would be an ideal choice as it has the ability to be very bright for a large well lit room where its greater size, weight and increased noise will not be important factors. However for our home cinema user the LED model is best suited as no fan is required to cool the light source, no colour wheel is present thus making noise minimal and the size most compact. The light weight is also beneficial for either being able to move the projector easily or ceiling mount it without any structural issues. A standard bulb projector would work well here too for those on a budget - albeit sacrificing some size, weight and noise.
Up to now we've only mentioned projectors designed for installation or minimal movement, however there is a range of portable projectors that are designed for ultimate movability. They are so small as to fit in your hand and aimed at projecting video from laptops, smart phones or even from a USB stick or SD card so no other device is required. Portable projectors are usually based on LED technology s as these offer the most compact design, the lightest weight and fewer moving parts, having no colour wheel, so they are also at less prone to damage when being moved.
Given their compact size and weight (under 1kg), it is perhaps not surprising that portable projectors aren't very bright (1000 ANSI lumens maximum) and their resolution is limited (sub FullHD), but it is worth remembering that they are designed for impromptu gatherings or presenting on the move without a screen so these restrictions are easily outweighed by the ability to watch videos from your smartphone in a much bigger format.
Projectors usually have a number of interfaces available for you to connect them to your AV equipment or PC, and in this section we'll look at each one you're likely to find, some details about it and advise which one is best for given applications.
HDMI is a combined audio and video option that is also widely used by TVs, offering up to 10K resolution at 120Hz. You have to work within the bandwidth limitations of whichever HDMI specification you're using, as the standard has evolved multiple times since its introduction in 2002. You can see this as a version number, with the table below showing the principle differences between the recent versions of DisplayPort at 1440p and 4K, the most popular resolutions.
| HDMI Version | 1.3/1.4 | 2.0 | 2.1 onwards |
|---|---|---|---|
| Maximum Refresh Rate at 1440p | 75Hz | 144Hz | 240Hz |
| Maximum Refresh Rate at 4K | 30Hz | 60Hz | 120Hz |
DisplayPort is a combined audio and video option that offers up to 16K resolution at 60Hz. The main advantage of DisplayPort is the ability to output to multiple displays through Multi-Stream Transport (MST). You can do this by daisy-chaining compatible monitors over DisplayPort to your single DisplayPort output on your PC or laptop. You have to work within the bandwidth limitations of whichever DisplayPort specification you're using, as the standard has evolved multiple times since its introduction in 2008. You can see this as a version number, with the table below showing the principle differences between recent versions of DisplayPort at 1440p and 4K, the most popular resolutions.
| DisplayPort Version | 1.3 | 1.4 | 2.0 onwards |
|---|---|---|---|
| Maximum Refresh Rate at 1440p (uncompressed) | 240Hz | 240Hz | 240Hz |
| Maximum Refresh Rate at 4K (compressed with DSC) | N/A | 240Hz | 480Hz |
| Maximum Refresh Rate at 4K (uncompressed) | 120Hz | 120Hz | 240Hz |
DVI stands for Digital Visual Interface, and is another common connection found on PC monitors. Things can become a little confusing when you consider there are several types of DVI. There is DVI-D (digital signal) and DVI-I (integrated analog and digital signal). Not only that, but both have single-link and dual-link versions. The differences between single-link and dual-link refer to how much bandwidth the cable can carry - single link supports 1200 resolution whilst dual link tops out at 1600. It also supports a FullHD (1080) resolution at 144Hz refresh rate - ideal for gaming.
VGA is the oldest of the connections you may find - it stands for Video Graphics Array but can also be referred to as an RGB connection or D-Sub. While VGA can technically output to FullHD (1080p), the problem is that it's an analog connection, as you push the resolution higher you get image degradation as the signal is converted from analog to digital. Unless you absolutely have to, use one of the newer connections instead of VGA
Ethernet can be used to connect a projector - usually within a corporate network. Ethernet cables normally support industry standard data transfer speeds of up to Category 6 (CAT6), meaning they're capable of transmitting video, audio and data up to 4K resolution.
USB is a common and versatile connector on projectors nowadays. It can be used to connect a standard USB cable and transmit video and audio this way, or without an external source using a USB thumb drive. This latter option is very convenient if multiple users are using the projector.
Component Video is a video only transmission cable, and may also be known as 3 RCA, YPBPR or YCBCR. The signal is separated into 3 channels of red, green and blue and transmitted. It is capable of supporting up to FullHD images, however it should be noted that this is an analogue connection so the signal is subject to interference and potential image degradation.
S-Video is an older connection technology that operates by separating the chroma (black and white) and luminance (colour) signals and transmitting them via separate pins. It can also be called SVHS, Y/C or Mini DIN.
Composite Video is another video only connection type and is also known as single phono, 1 RCA or cinch video. Composite video connections combine the colour and black and white signals of the video transmission. Generally, the video is transmitted in 480i or 576i standard definition image quality.
In order to achieve the maximum picture quality from your projector it is highly recommended to use a projector screen. Projector screens use a matte finish fabric with a special reflective coating to maximise picture quality, by reflecting and diffusing the light back at you. Transversely, if you project onto a white wall most of the light is absorbed rather than reflected, resulting in loss of image sharpness, contrast and brightness.
It is also important to choose the correct size for your room. Whilst a larger screen may sound appealing, you don't want to crane you neck or move your head to see all the picture. A 16:9 aspect ratio is ideal for most settings but if your predominant or sole use is high-end home cinema then a wider format will suit.
Screens can either be wall mounted (fixed or roll down), ceiling mounted (roll down), or floor standing (roll up). A floor standing screen may only be ideal if portability is required. Whilst a wall mount fixed frame screen may be the cheapest option in large sizes, they are always visible so may not be the ideal choice especially in the home. However, both wall and ceiling mounted rollable screens can be removed from sight and can be either be manually or electrically operated.
Electric screens will obviously increase in cost, but offer convenience as they can be controlled by either a wall switch or remote control. Ceiling mount screens can also be recessed so the screen is barely visible when not in use, but again this feature will increase cost.
Having said that a screen is recommended, it is possible to get good results using a wall either inside or outside, so long as you prepare the wall surface properly. Firstly, you'll need projector paint - designed to be reflective - either grey or white is recommended depending on the brightness of your projector. You will also want to ensure the surface is as smooth as possible - well sanded and free from bumps, chips and flaws as these will show up in your images.
In many instances it makes sense to mount the projector rather than having to move it around each time you want to use it, and there are many choices. Ceiling mounts, ceiling lifts, wall arms and security cages are just some of the ways to consider mounting your projector. Remember though that you'll have to take into account the size & weight, the throw distance, and whether the projector requires mounting upside down. If this is the case the image needs to be flipped so ensure to check that this mode is supported before opting for a ceiling mount.
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A projector is an optical device that displays images, videos, or data onto a surface, such as a screen or wall. It works by emitting light through a small, transparent lens, or using lasers, which magnifies and focuses the picture for a large-screen viewing experience.
You can buy a range of Full HD and 4K projectors from Scan. You can learn more about their features and suitability by reading this buyers guide.
A projector screen is generally advisable. It will provide significantly better contrast, colour accuracy, and brightness than a plain wall. While a smooth white wall may work in a perfectly dark room, a dedicated screen enhances image quality, overcomes surface imperfections, and increases brightness.
While a projector can be used as an everyday TV, it is better to consider the specific use cases as to when you would benefit most from a large screen that a projector provides. Gaming and films would be best viewed on a large screen, whereas regular television broadcasts may be better suited to a convenient TV screen without the need to set up a projector / dim the room.
Laser projectors excel in high brightness, contrast, and colour accuracy, making them ideal for dedicated home cinema use or in bright rooms, while LED projectors are often more compact, affordable, and portable, offering good colour with lower brightness and heat. Both technologies offer long lifespans (20,000+ hours) and instant on/off compared to traditional lamps.
To choose the best projector for gaming, you should prioritise a resolution of 4K, low input lag (under 16ms) for responsiveness, coupled with high refresh rates (120-240Hz) for smoothness, and at least 3,000 ANSI lumens if gaming in bright rooms. Connections including HDMI 2.1 will provide the best connection to the latest gaming PCs and consoles - however 1080p will still provide cost-effective, high-speed competitive gaming.
To choose the best projector for home cinema, you should prioritise a resolution of 4K, high brightness (2,000+ ANSI lumens), and laser technology for longevity. You could consider an ultra short throw model in small rooms or a standard throw model for dedicated cinema rooms, where you may also want to consider a ceiling mount for the best experience.
To choose the best projector an office environment, you should prioritise a brightness of at least 3,000–4,000+ ANSI lumens to combat ambient light, and a native 1080p (Full HD) or WUXGA resolution for crisp text. Additionally, opt for a laser light source as this will give better longevity and lower maintenance. Lastly, choose between short-throw for small rooms or standard-throw for larger spaces. It may be wise to ensure the projector has dual HDMI ports for multiple devices and wireless screen mirroring for flexibility.
To choose the best projector a classroom, you should prioritise high brightness (3,000–5,000+ ANSI lumens - depending on room size), full HD resolution for text clarity, and a laser light source for longevity and minimal maintenance. Short-throw models can be better for smaller spaces, as they reduce shadows and glare. It may be wise to ensure the projector has dual HDMI ports for multiple devices and wireless screen mirroring for flexibility.