Lumens:
A unit of measurement of the amount of brightness that comes
from a light source. The standard lumen rating of a data
projector is the average of photometer readings at several
points on a full white image on the screen. Technically, lumens
measure "luminous flux." A wax candle generates 13 lumens; a 100
watt bulb generates 1,200. All of the specifications on our site
are in ANSI Lumens, ANSI or American National Standards
Institute is a standardized measurement system that can be used
to compare projectors.
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Projection Brightness _____________________________________________________________________ There is more to image quality than just resolution. Brightness uniformity is also important. Uniformity is the percentage of brightness carried from corner to corner and edge to edge of your image. A higher uniformity rating means better consistency throughout your image. For the most consistent images, look for a uniformity rating of 85% or better. Brightness is measured in a number of way, most commonly ANSI lumens.
Measurement
Foot-lambert: Measurement of light emitted or reflected from a surface. The higher the rating, the brighter the picture. One foot-lambert is equal to the reflected light radiated by one candle over a one-square-foot area.
Lux: The International System unit of illumination, equal to one lumen per square meter. Also called candle-meter (cd/m²), Primarily used for projectors with lower lumen output.
In order to select how bright a projector you will need, three factors need to be considered::
How Bright Should Your Image Be "Sufficiently
bright" has been defined by Society of Motion Picture and Television
Engineers (SMPTE) in standard 196M as 12-22 footlamberts (41 - 75 cd/m2),
though often 16 footlamberts is taken as the nominal goal.
It should also be noted that the eye's sensitivity to colors is strongly correlates to brightness, Hence, increasing the brightness of the image gives it a more vibrant look, thanks to the better perceived colour saturation. Room Brightness
Firstly I'd like you to consider why commercial cinemas are dark? Its because even the brightest commercial projectors and TV's for that matter, Do not like light! No matter how much money you are willing to spend if you want to improve your image greatly, reduce the ambient light. This will maximize your projectors potential and allow you to use a lower lumen projector and achieve the same result. the other positive is that most high lumen projectors have a shorter lamp life around 1000Hrs. Many sales staff say "You can watch it in daylight" Ok yes you can, but Lumens or brightness can only help the bright part of the projected image, blacks in the image are not projected, light is switched off. If you watch in daylight the dark areas of the image which are not projected will look grey and washed out. If you have no option but to project in a lit room, you will need the extra brightness and a higher contrast ratio. If your room is very well lit, such as full fluorescents, you will need more lumens. If the room were to have half of its ambient light, you would need half the lumens. Rooms with minimal lighting will require a far less powerful projector which saves you money.
Screen Size
The
bigger the screen, the more lumens you will need. If you double the screen size
- say from 60 in. diagonal, to 120 in. diagonal, you will need a projector with 4 times the
brightness. If you think of a torch shining on a wall the larger the beam the
lower the brightness. So a good idea is to work out the size of the image you
want. This is not just as big as the wall. As a rough guide remember that you
should be at a distance from your screen less than 1.5 times its diagonal for
that real cinema feel.
Type of Presentation
Brightness of projectors:
Less than 1000 lumens - these are bottom of
the lumens range and they are typically LED Projectors.
If budget is an issue there are many projectors in this range. At this level
image size has to be small and
ambient light has to be kept very
low.
1000 to 2500 lumens
2500 to 5500 lumens
5500 lumens and up
We recommend the following lumen outputs:
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