Lumens and NITS are units of measure, of light; lumens for video projectors and NITS for video displays and televisions
(See “Display vs. TV, what’s the difference?”).
Let’s look at projectors first. Video projector brightness is measured, and to be a little more specific, in ANSI (American National Standards Institute) lumens. A little history here, ANSI was founded on October 19, 1918, and is headquartered in Washington, DC. Simply put, many manufacturers worldwide voluntarily adhere to these U.S. standards for the purpose of apples to apples comparisons.
One ANSI lumen is the amount of light that a typical birthday-sized candle (yes, a birthday cake sized candle) gives off in a one square-foot area. Video projector ANSI lumen ratings vary from as low as 600 for a dark home theater to as high as 60,000 for an IMAX projector. Some typical recommendations for commercial presentation projector brightness are:
- A small room with the lights off, 2,500 ANSI lumens
- A medium-sized room, for up to 50 participants with some ambient light, 3,500 ANSI lumens
- A larger room for as many as 150 participants with some ambient light, 4,500 ANSI lumens
- And the same sized, larger room with the lights on, 6,000 ANSI lumens, or more
A video displays light output is measured in NITS. The closest we could come to the acronym’s origin is the Latin word nitere (to shine) and is believed to be the likely source. A NIT (the acronym for nitere) is the amount of light output equal to one candela per square meter. To keep it simple, a candela is a different unit of measurement than a candle, and in comparison, one NIT is almost three and one-half times as bright as one lumen.
A typical commercial display used in a huddle-space, say 40-inches will likely have a brightness of 400 NITS. In comparison a high-brightness 55-inch commercial display used for digital signage in a well-lit space will likely have as many as 2000 NITS!
A quick comparison for video projectors vs. video displays:
- 400 NITS is equal to about 1,350 ANSI lumens
- 1000 NITS is equal to about 3,350 ANSI lumens
- 2000 NITS is equal to about 6,650 ANSI lumens
Whether you choose a video projector or video display, and in most applications when it comes to brightness, the higher the number, the better. This is because you can always adjust the brightness down if it’s too bright…but, and a BIG but, you cannot raise the brightness more than it is rated for!
We also want to touch base on image size. This is a critical aspect that must be determined in advance of your choice, be it a video projector or display. After you determine the brightness, you must determine the size, typically measured diagonally from one corner to the other corner of the displayed image.
Not to generalize too much, but typically for a general presentation with some text, you divide the distance the furthest viewer is from the screen by 6, to give you the screen height. A quick example that for a 20-foot distance you would want the screen height to be 40-inches. That will translate for a 16:9 format image, to about an 80-inch diagonal image (that’s over seven and one-half feet!). This calculation changes if you are viewing images that require detailed inspection. FYI-more to come on the “format” or “ratio” of height vs. width of an images size.
Brightness and image size go hand-in-hand! If you have the right brightness but the wrong size image you won’t be able to read the numbers on your Excel spread sheet…and vice-versa, if you have the right size image and the wrong brightness the image will be washed-out and you may not be able to read the numbers on your Excel spread sheet.
Don’t worry though, we can help. Whether you are in the design phase and just have drawings for a space you are building or already have a space you want to add or upgrade your video system our team of industry certified account managers and audiovisual engineers will design a video display system that will match your needs and exceed your expectations, guaranteed!