Measuring Florescent light output

[The Peloric Orchid]

I strongly recommend buying a lux or footcandle meter. I got one for around twenty bucks on Amazon (just remember that there's around 10 lux per footcandle). That way you can take the guesswork out of light placement. The main downside with these kinds of meters is that they're calibrated to more sensitive in the green/yellow range, much like human eyes, so they won't measure colored light accurately. The alternative is to buy a PAR quantum light meter, but these are much more costly and there's less data about orchid growth in light levels measured in micro einsteins.

[Stray59]

Again - WOW !I am amazed that something so widespread in it's use seems to be so complicated to properly implement. You guys keep up the discourse. This is all WAY over my head so I will keep monitoring until it gets really simple - I am a little . And a lux meter sounds like what I need to invest in. Any suggestions to brand or what to look for exactly?
Steve
p.s. - what in the heck is a micro einstein?

[The Peloric Orchid]

Since most meters are for lux measurements, I recommend one that's rated for at least 50,000 lux (which converts to around 4600 footcandles). That way you can make measurements all the from low light to something that's beyond the brightness require of bright light orchids. Unless you're into professional photography, you don't need to spend more than $35 dollars on a light meter.

A micro einstein is basically a measurement of the number of photons. As far as plants are concerned, most photons that fall within visible light are suitable for photosynthesis, so color doesn't matter in terms of a plant being unable to photosynthesize and quantum light meters are calibrated to reflect this.

Even though I have science background, the math and physics behind light went over my head too the first time I tried doing this. When I was trying to figure out what wattage (before I knew about lumens, lux, and footcandles) lights I needed, I realized that there wasn't enough data out there to make an exact calculation, so I bought a brighter light than I guessed that I needed figuring I could always mount it higher.

[Stray59]

The Peloric Orchid:
Thank you for the explanation. I am really non-mathematical; I always focused on psychology and orchids, or for that matter, anything besides math. I had a traumatic experience involving formulaic equations I think - I've all but blocked it from my mind. Needless to say, I am much better with epiphytic roots than square roots. I do have a Rhynchostylis that grew a square root, but I think it was just a fluke !
The answer to my question is a light meter. This is the simplest and most logical solution as I am sure every light bulb configuration, the distance of the bulbs, hood color, etc. makes a difference and a meter will show me what the plants are getting in my (their) home.
Thanks again for the help!
Steve

[DavidCampen]

Originally Posted by The Peloric Orchid

I strongly recommend buying a lux or footcandle meter. I got one for around twenty bucks on Amazon ... The main downside with these kinds of meters is that they're calibrated to more sensitive in the green/yellow range, much like human eyes, so they won't measure colored light accurately. The alternative is to buy a PAR quantum light meter, but these are much more costly and there's less data about orchid growth in light levels measured in micro einsteins.

The PAR light meters just do not have the green filter that other light meters have. The frequency response of a photocell without a filter is fairly flat so a green filter is added to make the response more closely match that of the human eye.

The inexpensive light meter that I bought on Amazon had a green filter that I easily removed. Of course, that messes up whatever absolute calibration the meter may have had but if you only care about comparing relative values for varied light sources - sunlight, fluorescent, red LED etc. it now matches the PAR meter response.

[Stray59]

Good info to know - I am still in the undecided stage at this time, so I will still just monitor the conversation as see how this develops - I am either somewhat understanding what everyone is saying, or becoming delusional and in that case this really doesn't matter does it? I am leaning toward the meter you are talking about. Any idea of the name of the distributor?

Steve

P.s. I finally found a place to use the chicken emoticon - Yes!