# Are LUX and LUMENS proportional

@dbrn32
I have modified an LED bulb by removing most of the bulb and added a reflector (aluminum duct tape) to the remaining section of the bulb. Obtained the following LUX readings 12 inches from the bulbs: unmodified bulb 2803 lux, modified bulb 7637 lux.
My question, if the LUX reading increases by a factor of 2.7, does the lumen rating increase proportionately?

Luminous flux is measure of total light output, it wonâ€™t change by adjusting height. Lux is measured light intensity, like lumens per square foot. That is what changes by adjusting height. So you can manipulate the light intensity by adjusting height, but not the total amount of light emitted by the bulb by any factor.

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Hahaha, I Literally Just looked this stuff up yesterday, hope it helps! I needed it to see what my canopy is aroundâ€¦ these are not exact, the conversion is weirdâ€¦But these are Good Approximations I believe. PPFD to LUX is bigger numbers PPFD to Lumens.

I donâ€™t know the conversion factor off the top of my head, but itâ€™s dependent on light spectrum some. And Iâ€™m having a hard time grasping that anything measuring 39,000 lux would hit 1500 umols/s/mÂ˛. 3000k 80cri conversion for 39,000 lux is 568.38 umols/s/m2.

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I used a conversation calculator on Google soooooâ€¦ your guess is as good as mine LOL. Had to pick the lights used so mine are the burple r/b/w it says to use and that what came up, idk. I Just use a Lux/Lumen phone app for nowâ€¦ but trying to get a ballpark where the lights I have areâ€¦ true watts are only 480 for me, i want 600-650â€¦ for a 4x4x80 Your the Expert on lighting! I still cant really make head or tails of itâ€¦baby steps they say, Lol

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I am trying to measure light intensity with a phone app too, but my phoneâ€™s sensor wonâ€™t show anything over 30000 lux, wich apparently is about half of what you would wantâ€¦
I also found this â€ślux to ppfd converterâ€ť on google, and that one says that 30k lux on a blurple is about 450 umol/s m2 or something like thatâ€¦
What app are you using?

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That sounds petty reasonable. I believe apogee has some conversion calculators.

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Here is a good converter Lux to PPFD
https://www.waveformlighting.com/horticulture/convert-lux-to-ppfd-online-calculator
They have others too like DLI and others at bottom

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Yes thatâ€™s the ones I used, couldnâ€™t remember the site!

What kind of numbers should i be looking for? 6, seedlings 3 days old in a covered grow tub, 1200 virspectra burple, (seedllings only) at 24â€ť above seedlings,

Thanks

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Got me really. I donâ€™t measure, just put them under light and watch how seedlings behave and adjust as needed. I think most of the books suggest between 200-300 umols/s.

ok, thats what im doing,

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