quote:
Originally posted by inteller
I got a handy 5 in 1 multimeter for Christmas to measure nuisances. it measures lux, but I was mainly interested in measuring nits from all of the glaring LED signs popping up everywhere (since that is how they are regulated). Does anyone know what the difference is between nit and lux as far as being able to convert between the two?
"Nits" is an obsolete lighting term that was a synonym for "Candellas per Square Meter" or (cd/m²). For some reason the sign industry has chosen the obscure metric for it's new technology, but cd/m² is always used to describe the brightness of video screens and LEDs.
"Lux" is the Euro equivalent of the American "Footcandle" measurement of light. For rough calculations, 1 Footcandle = 10 Lux (just move the decimal point)
Lux is lumens per square meter, as opposed to
Footcandle which is lumens per square foot.
Nits or cd/m² is a measurement of Luminance, where
Lux or Footcandles is a measure of
Illuminance.
Luminance is light emitted from a given area, where Illuminance is a measure of light striking a surface.
Are we having fun yet?
Since the relationship between Lux and 'Nits' is derivative, it might help to look over the page at:
http://en.wikipedia.org/wiki/LuxSpeaking of obscure, sign-industry-written zoning code in Tulsa allows billboards to be lit to 70 footcandles, but gives no method as to where or how that is to be measured, so there is no enforcement. When you consider ONE footcandle is roughly the light on the street surface directly underneath a residential streetlight, you can see there is a lot of slop in the way we light things.
Just for fun, take an illuminance meter to your local gas station for some real mind-blowing numbers.