Choosing an Education Projector: Specs and Features
Several additional features impact an education projector’s overall picture quality. This holds true for interactive, short throw, and network projectors.
Most education projectors are based on DLP or LCD technology. Digital light processing (DLP) is the most-used projector tech for all types of applications. This includes the most basic projectors to the most advanced, such as those used in high-end digital theaters.
All projectors use some type of light source to create projected images. There are three options: LEDs, lamps, or lasers.
LEDs are used in pico projectors – tiny models designed to be extremely portable. Many are so small they can fit in a pocket or purse. They can be a great way to extend resources among classrooms. LED light sources are eco-friendly; they consume less power and generate less heat than traditional bulbs. They are also mercury-free, for easier disposal and less hazardous waste. Due to the fact that LEDs do not contain a filament, they last significantly longer than traditional bulbs. They power on in an instant, for fast start up – another reason they’re great classroom projectors. LED projectors are also cooler and quieter to operate than lamp-based projectors. On the downside, LED-based projectors are typically not as bright as those powered by other light sources. This can limit their use in some applications. In terms of lifespan, LED-based education projectors reign supreme, with over 30,000 hours of operational life.
Lamp-based education projectors have existed the longest and are the least expensive. Because of this, they can be cost-effective for lower-use applications. They are the most common classroom projectors. For frequent use, however, the need to replace bulbs and clean filters increases their total cost of ownership (TCO). Lamp replacement can also cause downtime, interrupting class when a bulb unexpectedly blows out. Lamp brightness and color tend to fade as well. However, the impact of this is often minimal because it happens over time. The lifespan of lamp-based projectors is shorter than LED- or laser-based projectors; typically 10,000 hours. Traditional bulbs are also the least eco-friendly option as they contain mercury and require appropriate disposal to minimize harm.
Laser lighting is the latest thing in projection light source technology. Education projectors with laser light sources have a higher up-front cost, but can be quite cost-effective over time. This is due to their longer lifespan and lower maintenance needs. Laser projectors deliver precise color and high brightness levels that remain stable across their 20,000 hours of life. Another helpful feature for education is an instantly enabled on/off system. Unlike lamp-based projectors, lasers do not need a warm-up period. This adds efficiency and conserves valuable class time. Finally, they consume less power than traditional lamp-based projectors. Laser lighting is a mercury-free, eco-friendly option.
Color Processing Technology
Most education projectors will include some type of technology to enhance color performance. One of the better known is BrilliantColor™ by Texas Instruments. Some manufacturers offer proprietary tech to expand upon BrilliantColor™ benefits to include ViewSonic SuperColor™. This unique color wheel design delivers higher brightness and a wider range of true-to-life colors. The result is an immersive viewing experience in any lighting condition.
Benefits of advanced color processing technology include:
- Consistent color performance in both bright and dark environments
- Advanced color wheel design
- Expanded color range
- Dynamic lamp control capabilities
- Automatic or one-touch color/brightness adjustments
- Enhanced gray-scale accuracy
- Minimized brightness fluctuations
Native resolution refers to the number of pixels a projector has available to create an image. It is typically shortened to simply: resolution. The first number represents the number of pixels in each horizontal row, whereas the second is the number of pixels in each vertical column. Multiplying the two delivers the total number of pixels the projector can display. The higher the resolution, the more pixels.
Resolution is the number of dots or pixels used to display an image. Higher resolutions mean that more pixels are used to create the image resulting in a crisper, cleaner image. High resolution is important for projecting detailed charts and graphs, text, and high-definition video. The resolution is represented by a number combination such as 1920 x 1200. This indicates that there are 1920 dots horizontally across the display by 1200 lines of dots vertically, equaling 2,304,000 total dots that make up the image seen on the screen.
Higher-resolution education projectors can display a greater degree of detail. They reduce or eliminate visible pixelation, for crisper viewing at a closer range. These projectors are more compatible with high-definition source content. For the most part, as resolution increases, so does cost. In general, for classroom use, ultra-high resolution is not needed for typical viewing material. Exceptions may include specialized classes with high-detail content such as science, technology, or math.
A related spec is a projector’s “maximum resolution.” Native resolution refers to the total number of actual pixels displayed. Maximum resolution has nothing to do with the projector’s physical display. Instead, maximum resolution refers to which content signal resolutions the projector can display. Projectors are programmed to recognize and process a number of these signals, based on their popularity in a given market. Maximum resolution is the highest signal resolution that a projector is programmed to process and display.
Projectors can convert signal resolutions that differ from their native resolution. To do this, they use a process called “scaling.” When a signal exceeds a projector’s native resolution, the image is compressed into fewer pixels. When a signal has a lower-than-native resolution, the projector must expand it in order to display a full-frame image. When source material is scaled, there will always be a loss of signal quality. This results in a somewhat softer image compared to the same material displayed at its native resolution. For many classroom uses, this will rarely be noticeable. However, it can be problematic in some circumstances, including projection of data such as text or mathematics content.
The resolution abilities of any education projector are limited by the native resolution of your source material. Low-quality signals result in lower-quality images. This is the case regardless of the projector’s native resolution. The larger the screen, the more noticeable this will be. To achieve the best image quality, match the resolution of the content to the projector’s resolution.
Thankfully, video scaling technology has advanced considerably. Today scaling can produce images nearly as crisp and clear as they would be displayed in a native format. For displaying data content, matching projector-source resolution is more critical.
The most popular resolutions for education projectors include:
- 800x600. With an attractive price and great image, SVGA is a popular resolution. It is a good option for basic presentations. PowerPoint slides on a 60" screen (or smaller) will look clear, as will other basic applications like simple data, charts, and videos. With a 4:3 aspect ratio, the price range is from $200 to $450.
- 1024x768. This resolution is also referred to as XGA. It generally delivers good image quality for native DVD video and 1080p Blu-ray content. Additionally, 1080i HD broadcast content can be scaled for reasonable quality. Visible pixels can be eliminated by sitting further from the screen. These projectors have a 4:3 aspect ratio and vary in price from around $349 to $649.
- 1280x800. This hybrid resolution (WXGA) can natively display 720p HD video. This format delivers crisp, clear viewing for computer data, web pages and video from computer-based data signals. The tradeoff is the 16:10 aspect ratio, due to the fact that a standard aspect ratio is 16:9. With WXGA, 16:9 video content is displayed with black bars at the top and bottom of the projected image. However, 16:10 is becoming more widespread; it is now the standard for many laptops and smartphones. Pricing for WXGA projectors ranges from around $379 to $699.
- 1920x1080. Also known as Full HD, this resolution offers a high total pixel count. Full HD delivers sharp, detailed images. These education projectors are a perfect match with high-definition content sources. They are compatible with HDTV 1080i and 1080p signals from Blu-ray disc players and do not require scaling. Prices for classroom and home-theater 1080p projectors range from $499 to $849.
- 1920x1200. A newcomer, the WUXGA resolution is the widescreen version of 1080p. It has 16:10 aspect ratio, delivering added pixels and greater height to the projected image. It has become the standard for higher-end laptops and PCs. WUXGA offers higher-brightness and is ideal for higher-ed and auditorium installations. The added pixels make these education projectors a great fit for detailed source content such as web pages, presentations, spreadsheet data, and design software. This makes it a good option for specialized teaching environments. WUXGA projector prices are around $849.
- 3840x2160. This is the 4K ultra-high definition (UHD) resolution familiar for its popularity with TVs. 4K education projectors deliver bright, highly-detailed images. They are ideal for lecture halls and auditoriums. Ultra-HD is also a great choice for specialized topics that call for precise detail. Prices range from $999 to $2,199.
Contrast ratio is the difference between an image’s white and black components. For example, a contrast ratio of 1000:1 indicates that the black levels will be 1000 times darker than the white levels. The larger the contrast ratio, the greater the difference between the brightest whites and the darkest blacks a projector can display.
In general, a projector’s ability to create image depth increases along with contrast ratio. It’s an important spec for home theater projectors and other high-end uses. It is less critical to the needs of a typical classroom; the benefits of high contrast ratios are only noticeable in highly light-controlled spaces. Therefore, a high-contrast ratio education projector would be a good choice for lecture halls and theater spaces. However, in a typical multi-use classroom, projectors are used with some degree of ambient light. For these settings, contrast ratios of 4,000:1 – 10,000:1 are sufficient to deliver a satisfying visual experience.
Projector brightness is measured in ANSI lumens (or simply, lumens). Brightness output ranges between 500 and 10,000 lumens. Most environments do not need a high-bright education projector to achieve satisfying results. In addition, the brighter the image, the more costly it the projector will be. To determine your brightness needs, consider your ambient lighting and the size of the audience and screen.
Ambient light is the most critical factor in determining the best education projector brightness for your needs. The more light you have during viewing, the higher the brightness you’ll need to deliver a sharp, clear image. For most classrooms, instructors want a moderate level of lighting during projection. This allows for eye contact, interaction, and safe movement around the room. In these cases, a mid-range brightness of 2,500 to 3,500 lumens is generally a good practice. This range offers the flexibility to project in a range of lighting conditions. However, if the room will always be darkened, or always be lit, you will want to choose a projector on either end of the brightness spectrum. Keep in mind that a projector bright enough to shine through a great deal of ambient light will be hard on the eyes in a dark room. Conversely, a low level of brightness will look washed out in a room with lots of ambient light.
Audience Size/Screen Size
The larger the projected image, the lower the perceived brightness of any projector. This is due to the distribution of light over a larger area. The typical number of people that will be in a room is a good guideline for picking your education projector. It can help you determine the optimal projected image size for comfortable viewing.
The more people in the room, the larger the ideal screen size needed. Typical classroom projection size ranges from around 60 to 80 inches (measured diagonally). An average audience size is 20-30 students, creating conditions ideal for 3,000 to 5,000 lumens.
Larger spaces, such as lecture halls and auditoriums benefit from higher brightness. For these spaces, it is recommended to seek a projector that offers 4,000 to 6,000 lumens.
Projectors can be grouped by ANSI lumen output as follows:
- Under 3,000 lumens. These education projectors are used in low-lighting environments. They require tightly controlled conditions to eliminate ambient light, making them appropriate for theaters. However, they are not typically used for multipurpose classroom viewing.
- From 3,000 – 4,000 lumens. Representing the mid-range of education projectors, these are the typical brightness levels for classroom use. Slightly dimmed lighting will produce the most vibrant images. However, the image will still be visible will full classroom lighting.
- 4,000 + lumens. Projectors with this level of brightness are typically not used in classrooms. They may be appropriate for large meeting rooms, classrooms, or multipurpose rooms. High brightness education projectors are ideal for large spaces like lecture halls. With this level of brightness, there is no need to dim lights. Users can expect a crisp, clear image with standard room lighting; even on larger screens. This enables ease of viewing with larger audience sizes.
Projectors with brightness ratings higher than 5,000 lumens are considered “high bright” and are intended for high-end commercial use. This can include installation in some higher education settings.
A projector’s aspect ratio does not directly impact the quality of the projected image. Nonetheless, it is an important spec because it determines the image’s shape and space occupied on the screen. Aspect ratio defines the relationship between the width and the height of an image. It is used to describe projection screens and content sources, as well as projectors. A 16:9 projector, projection screen, or content source will have 16 units of width for every 9 units of height; resulting in a rectangular shape. A 4:3 aspect ratio will have 4 units of width for every 3 units of height; resulting in a square shape.
As with resolution, challenges arise if the projector’s aspect ratio does not match the aspect ratio of the source content. Ideally, the aspect ratio of the projector, projection surface, and content source will be aligned. When these match, the image will fully cover the screen. When the content aspect ratio does not match that of the projector, a portion of the screen will remain unused. For example, when watching 4:3 content on a 16:9 display, there are black bars along the top and bottom or sides of the screen.
Most education projectors today offer the popular 16:9 aspect ratio. This corresponds to the familiar HDTV standard and Full HD 1080p desktop displays for computing. However, there are many other formats. For example, TV programs and videos made for non-HD TV are developed in the legacy 4:3 format, whereas dvd format differs.
There is no universal standard for video content and is highly unlikely that the aspect ratio of your education projector will always match up with all the content teachers wish to display. Fortunately, most projectors can scale images to fill all or most of the screen. Scaling inevitably entails some loss of detail. However, it is generally quite minimal and is rarely noticeable when displaying video and images. For curriculum that relies heavily on text-based content, matching the projector and source content aspect ratio is of greater importance.