# Measuring light...lux to k?



## RentaPig311

Long story short my new...lets say work space has an upper wall shelf with two 4ft long or so lights underneath. I'm looking to liven the place up a bit with some plants maybe a terrarium or something. I'd love to have a viv but I'm pretty sure they cut the a.c. at night. I've found smart phone apps for photographers that measure in lux. Is there a conversion formula or something than will tell me if this is in the 6500k range my plants love? If not is there an alternative without breaking the bank on a light meter.


----------



## mcaiger53

There isn't a conversion for lux to K, they measure different aspects of light. Lux = amount of light, and K (kalvin) measures the "color" of the light. A light with a lower K, say 3500 orso will appear slightly yellow. Higher K around 6500-8000 will be more white, and even higher around 15000 K is getting pretty blue.
If comparing light output to a water hose, lux/lumens would be like gallons per minute, and K would be like the color of the water (if it were dyed)
Lux and Lumens are measurements of light, though not completely sure how to convert/compare them?
Hope this helps
Mike


----------



## mordoria

if the light seems yellowish its around 3500k, think an old lightbulb lamp (yellow), a whiter light is 5000k, this is more natural color rendering and then the 6500k is crisper white/blue. Plants can use all the colors but 5000-6500k is usually standard for terrariums due to the natural look of the light.

You can test if they cut the ac at night. Get a thermometer that has a high/low memory. Itll tell you if the temps drop. Also, most offices stay the same temp year round. 
Whats the LUX youre reading when you place the phone flat on a surface?


----------



## RentaPig311

It reads about 1090 in lux. It looks like the "bright white" light I use over my frog tanks. I was just looking for a way to confirm. I don't want to kill any plants. Good idea on the temp gauge I will look into that for sure.

Sent from my DROID RAZR using Tapatalk 2


----------



## mordoria

wow, thats pretty bright.


----------



## skanderson

i think you need to divide that number by 74 to get ppf, which is what my apogee measures. just for comparison my measurement at the floor of my viv varies from about 80 to 100 ppf. up near the lights it is much closer to 200. that means my low light level is somewhere from 5500 lumens to 7400 lumens at the floor up to a max of 14800 lumens up high in my viv. so 1000 lumens really isnt that bright. you need to watch the units and the conversion factor. i got my conversion from the apogee website using the numbers for cool white flourescent which is what most offices are lit with. i would bet that the color temperature is probably sufficient but that the lumens are on the low side. you could probably keep the lower light stuff happy with that though, just dont expect your red noreglia broms to keep good color. just to recap the lux,lumen,ppf ideas lumens and ppf are both a measurement of the number of photons. the lumen scale is slanted towards what the human eye is sensitive to while ppf is slanted toward photosynthetically active photons. lux on the other hand is a measurement of photons per area. this page may be helpful Apogee Instruments FAQs - Conversions from Lux dont know if it will work as a link or you need to type it in.


----------



## Pumilo

*Re: Hello to harry*



Nurfcarma said:


> Hello to human being on this fine-looking forum. Welcome me further myself. I am connoisseur and i am running this site :
> <a href="http://www.yayinakisi.com">ligtv </a>
> Waiting to all these friends.
> Best regards


You must truly be an amazing person. According to your posts you are a connoisseur, engineer, pilot? (plot), the competition?, an engine driver, a doctor, my mistress?, and a schoolmistress.
I would love for one of our mods to give you a nice warm welcome.


----------



## Kierik

Can't tell if your a troll or just bad at picking a name for a spammer. Nurfcarma = nerf karma? 

As far as office lights I have grown many plants under them but never vivarium style ones. I did have a guava seedling do very well under them. I would expect that they will be fairly weak in lux and par but you can always try and if its an under cabinet light remove the diffusser. You could also see what happens if you swap out the bulb for a 6500k bulb, or ask for permission. You could always claim that you like your working light more yellow. 

Sent from my DROID3 using Tapatalk


----------

