Light output is a casual term used to define how much like a fixture produces as well is how well it distributes that light. The formal approach of using data to describe the quantity and distribution of visible light production is photometrics. There are a variety of different photometric instruments which are designed to test different types of LED at a variety of angles. These instruments provide consumers with significantly more information than what is provided by conventional lighting fixtures. Traditional fixtures report their performance based upon lumen output. A lumen is the standard unit of measurement which defines the total perceived power of a light source (more casually referred to as brightness). Unfortunately, this standard of measurement is not only inaccurate but can be particularly misleading when dealing with LED lighting fixtures Led armatuur.
Lumen output is consistently reference by traditional lighting fixtures because it downplays or underestimates the amount of light LED fixtures can actually create. This inherently distorts the fixtures performance suitability for any given task or application. A more relevant measurement for evaluating LED fixtures and accurately comparing them to conventional lighting fixtures is delivered light. Delivered light, formally referred to as illuminance, is the intensity of light falling on a surface area, typically measured in square feet.
The first reason measurement instruments should measure using illuminance instead of lumens is consumer understanding. The complete inaccurate definitions of lumens and similar photometric terms can become extraordinarily technical and complex. As a result, they are often misunderstood by the general public. Without a solid understanding of these terms the unique benefits and properties of LED sources cannot be easily compared to traditional lighting sources.
The second reason lumens are an imperfect method of measurement is because they rely on the perceived intensity of light sources. This has inherent shortcomings which are readily acknowledged by the lighting industry. Moreover, the properties of LED light sources naturally exaggerate the shortcomings, especially towards the blue end of the color spectrum.
Additionally, conventional lighting fixture manufacturers typically reports total lamp lumens rather than fixture lumens. This is because LED fixtures do away with the distinction between the two completely. As a result, only total fixture lumens can serve as a valid basis for comparison between conventional and LED fixtures.
Finally, instruments that measure total lumen output do not account for wasted light. LED are almost always directional and have the capacity to natively create white and colored light without filtering. As a result, they waste much less light than their conventional counterparts. Without accounting for wasted light, there are instances where LED fixtures look to be the less appealing option when in reality they are much better suited for the specific application because they have significantly less wasted light.
Article Source: http://EzineArticles.com/8078280