Color rendering is a measure of lighting quality. It is measured on an index from 0-100, with natural daylight and incandescent lighting both equal to 100. Lamps with a high color rendering index make objects appear more true to life. Plants can grow better with a higher color rendering index light source. But generally the higher the CRI the lower the lamp efficiency.
Color temperature is a measure of the color appearance of light not the actual temperature. Light sources that appear bright white to blue-white have a high color temperature (3600K and above) and are described as "cool". Sources that appear yellow-white to red-white have a low color temperature (3400K and below) and are described as "warm". Daylight is considered to be around 5500K and plants grown under this light do quite well. The cost of the lamp increases as the color temperature goes up because of the rare materials required to fill the arc tube.
A lumen is the unit that expresses the total quantity of light given of by a source, regardless of direction. A lumen is defined as the amount of light falling on a surface of one square foot, every point of which is one foot away from a source, (a section of the inside surface of a sphere) of one candlepower. A uniform source of one candlepower placed in a sphere emits 12.57 lumens.
Initial Lumens is the measurement of the intensity of the lamp Initially. Lamps do get dim over time and replacing them after 60% of the rated life is recommended for best performance.
|Description||Initial Lumens||CRI||Color Temp||Life|
|1000 watt Sodium||130000||21||2100||24000|
|600 watt Sodium||89000||21||2100||18000|
|400 watt Sodium||50000||21||2100||24000|
|250 watt Sodium||28500||21||2100||24000|
|1000 watt Halide||110000||65||3700||10000|
|400 watt Halide||36000||65||4000||20000|
|250 watt Halide||20500||65||4000||10000|
The table above is not a product guarantee, the specifications will vary slightly between different lamp manufacturers. The numbers above are an average of all our lamp suppliers specifications.