Light Meters?

[kg5]

Another question area! Thank You!

Will this light meter get me anywhere?

200,000 Lux LCD Digital backlight Pocket Light Meter Lux/FC Measure+Carabiner

[WhiteRabbit]

[kg5]

Looking at the search results here I can not understand if the light meter I am looking at is any good or not. Can not tell if this light meter reads lights that are blue green red yellow which I assume are UV light spectrums.

So I need to find out how much shade density is in my different shade areas? Or how much light is available to my plants from any given light?

Well I spent the money on the light meter I asked about. Hope it works. Hope it is what I need.

[naoki]

If it is not broken (there were some people here who got a fc/lux meter which gave really low values), it is probably good enough for your purpose. If you are using monochromatic (i.e. blue/red type) LEDs, then the reading from fc/lux meter is not that useful.

You might want to take a look at the first link in this thread: LED related links

Ideal fc/lux meters has the sensitivity response defined by CIE luminosity function. In other words, it is sensitive to green light, and not sensitive to red and blue light which is more relevant to plants. If you want to get a more plant relevant meter, you need something called quantum PAR meter.

Also, the sensitivity curve of most cheap light meters deviate from the CIE curve (and the correct response meters are really expensive). So I wouldn't put too much importance in the absolute values. Different light meter could respond differently.

You can measure the full sun light around noon, and check it registers approximately correctly.

Blue, green, red, yellow is not UV light. UV light has shorter wavelength than Blue light.

[kg5]

Thank You!

In the UV area there is many different types of UV that come with the same colour names and hugely different applications. Like UV-A which is green and UV-B which is blue colour etc all of which can seriously burn you and you can only be exposed to these lights for minutes before you start to seriously burn. I am best to leave the UV area alone because I have lots of different bits of info from very different areas of UV application and I just really do not know enough to clear the muddy waters.

I will stick to the mid day sun as a guide to understand my shade areas and trust my lights are good for growing. Great direction to point me into. Thank you!

But the big area is to get orchids that suit the different shade areas in our shade house which is all relevent to the sun or no sun for me. I am trying to stop the need to use growing lights.

My T8 fluro's in my 4' aquarium with 3 aquarium heaters in coffee jars for when they needed will be great for my flasks but not for growing orchids.

[naoki]

Normal human can't see majority of UV light (which is defined as < 400nm). Visible lights are considered to be > 400nm). Yes, you can categorize UV light into different categories. UV-A is closer to visible light, then UV-B, then UV-C etc. You can see the table in this wikipedia.

If you can feel the UV-A as "green", I would think the person is a bit abnormal (for a human). Bees (and insects can see UV light). So if you take the picture of flowers with UV light, you can frequently see patterns which isn't visible to human.

I haven't seen any studies showing UV is beneficial for orchids. For the plants you eat (or consume), UV light can influence production of certain chemicals. So UV could be beneficial for human (e.g. get some extra nutrients from vegetables). So I don't think you should worry about UV.

[kg5]

Yes plant UV is totally fascinating. I was getting a plant UV shade reaction images of the same plants one as a health plant and ones as different unhealthy same plants. The idea was to see what the insects can see as they always seem to attack the unhealthy plants 1st.

My reasoning was to use UV shade reactions as to understand the health of any given huge very important older trees. I never got to finish that work as I got really badly smashed up......Have not even spoken about this for over 20 years.....Sometimes things happen.....I had a huge budget and was able to think outside the square. Now it is just hot air. lol

[lepetitmartien]

First, all UVs are dangerous, for our skin and eyes. Don't play with at home. We need a little for ourselves for D vitamin synthesis, but more is playing with skin cancer… (and neither A or B are good.)

From all what I've read on plant photosynthesis, the UV capacity of absorption in photosynthesis is not of interest for orchid, or even can be dangerous. I'm sure you can have interesting results with bulbo from deep shade under UVs… In the killing department. (educated guess)

Some UV lights are good to kill bacterias and fungi, they are not that good for us either…

ANY plant under UVs will face the same issues as us, they can induce mutations by inducing errors in the DNA replication. It's because of UVs that on a tree, the roots DNA are not exactly the same as in the leaves, nor at the top of the trees. Don't expect it to be different on orchids.

Other plant families or plain sun orchids may have use of them or means to fight their effects.

On the "color" of UVs, well, we can as I do see near UV. When wearing 100% blocking glasses, after a moment when hiking in the Alps, I can see by looking sideways between the glasses and my skin that everything is violet. Don't do this much, it's not good for your eyes. If you see UV as green, I'd see a specialist, as you may have serious dischromatopsia (like daltonism is one for example).

I've bought a light meter really cheap, it's good enough to give an idea of the amount of natural light. Mind that what counts here is not the exact amount but the general figure. If you go into measuring the exact spectrum you go out of the usual amator cultivation and fine tuning maybe what doesn't need to be save if you're running a phal factory in Holland…

[kg5]

An image of a UV Longwave Shade reaction to detect type of red ink shade of a 1914/20 Australia KGV side face definitive stamp. There are 422 red shades recorded by a Mr Blogg in 1926.

UV image

[IMG][/IMG]

What is even more frightening is I have had 2.6 years of UV A & B treatment on my skin, that was more than 30 years ago.

---------- Post added at 07:15 PM ---------- Previous post was at 07:03 PM ----------

Had trouble posting both images in the one post so 2 posts it is.

The stamp in daylight shade.

[IMG][/IMG]

[ALToronto]

What you're seeing is not UV light itself, but the luminescence of another material (in this case, paper) during exposure to UV light. Most organic materials will luminesce, and some will fluoresce (emit their own light). About half of all diamonds fluoresce under UV.

Different wavelengths will cause different colour luminescence.

Your regular cool temp LEDs provide some UV already, you don't need more.