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View Full Version : Lumen Depreciation ??


Pothead4204life
06-12-2006, 10:11 PM
What percent of the lumens depreciate over distance? like for example 1 Foot?
bongerstonerd00d
06-12-2006, 10:24 PM
That answer your question.

http://boards.cannabis.com/attachment.php?attachmentid=67008&d=1148162259

http://boards.cannabis.com/attachment.php?attachmentid=67062&d=1148175556

First is for MH, second is for HPS.



b0nger
Pothead4204life
06-12-2006, 10:57 PM
thanks.
Zandor
06-14-2006, 02:06 AM
Lumens is a mathematical formula that measures the bulbs intensity at 1 foot.

The color or type of bulb is not calculated in the formula I=L/D²

Lumens received are a measured in watts-per-square foot or foot-candles. Calculating foot-candles or lux is a more accurate way to estimate the amount of light plants receive.

This still only measures how much light you plants have available but not how much your plants use.

Light diminishes exponentially fast!

The closer your plants are to the light the more lumens they receive the better they will grow, as long as the heat from the light does not burn the foliage
Zandor
06-14-2006, 02:14 AM
As I was trying to say but the post timmed out before I could finish...

The formula is I=L/D² so; 12? or less is all the same lumens so it??s 12? to 48? we have control of and the closer to the 12? mark the better because it provides the most lumens to the plant. To close and you burn the tips to far away and you give up luminance penetration (PAR). Next is Luminance loss. Most experts are in agreement that light intensity diminishes exponentially fast.

For example:
A 1000-watt MH from 0? to 12? is about the same luminance say 140,000 lumens

Same light at 24? the luminance is now about 30000