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Reviews-Filters for Fluorescent Lights

Hi all,

I'm looking for some advice from anyone who has actually used the filters marketed for fluorescent lights.  The answers to the computer monitor filter questions were some help- but I am asking about the type of lights used in schools.  Recently filters began being placed on all the lights at a local school in order to reduce flicker/ prevent seizures.  While that sounds great- several of the teachers began noticing that they were getting headaches by the end of the day and those who actually have seizures are getting auras or generally not feeling right.  No actual seizures yet but it seems like it may be just a matter of time from the teacher reaction- much less what will happen with students in the classroom.  The filters seem to be causing the problem that they are supposed to prevent.

Has anybody had experience with these filters?  Good, bad, indifferent?  Any advice you can give me is greatly appreciated!!


Re: Reviews-Filters for Fluorescent Lights

Hi Poppy1677,

I'm from the days of analog turntables for 78 and 45 RPM audio record-players. Back then, we checked the speed of the turntable using a cardboard disk with strobe markings on it. The strobe markings would "resonate" with the coordinating rings to measure the speed.

As the electrical power grid is at 60 cycles-per-second, the power is cycling through on-and-off at 120 times a second. Heavy filament incandescent light bulbs hide this on-and-off power the best, and these bulbs makes it difficult to use the cardboard disk to check turntable speed.

The earliest long-tube fluorescent bulbs connected in series with each other, without a ballast, came close to going through a "totally lighted" versus "totally dark" cycle at a 120 times a second, and the cardboard disk would work to perfection in utilizing the strobing effect.

Minimizing the strobing effect in light bulbs is a trade-off with energy efficiency. Some of the newer sub-compact fluorescent utilize a much better electronic ballast that greatly minimizes this effect, but at a trade off to the spectrum of the light.

Once the light leaves the bulb, filters only filter out undesirable ranges of the spectrum. Filters do not change the strobing effect itself. Though, some individuals are more susceptible to the strobing effect at certain parts of the spectrum. Diffusing the light from the bulb minimizes sharp shadows that would otherwise make strobing more easily detected by many people, but the light is still going through "bright" and "dim" strobe cycles.

Even with an electronic ballast, when the bulbs phosphorus coatings burn off and the anoded mercury vapor weakens, and/or the ballast malfunctions, the strobe effect often becomes visible with "walking" flickers along the spiral of the bulb's tube, usually resonating with the power grid's frequency, because even with the changing of the power frequency to around 40,000 cycles-per-second in the ballast, the power grid's 60 cycles per second is still primary.

Anyways, that's how my old analog old school memory remembers it, and down through the decades, all kinds of products were marketed to solve these problems with various gimmicks that never did quite work as well as they were touted.


Re: Reviews-Filters for Fluorescent Lights

Thanks for the info- it's easy to find these filters but impossible to get a product review or any sort of evaluation on their usefulness.  Just hoping to prevent a classroom full of seizures in September so if anyone has used these filters at their job please let me know what you thought of them!

Thank you!

Re: Reviews-Filters for Fluorescent Lights

Fluorescent lights are a great lighting choice for you indoor growing.
Whether you are growing vegetables, flowers or pretty much anything,
these lights should be able to support your plant enough for it to grow
strong and healthy.LED Bulbs

Re: Reviews-Filters for Fluorescent Lights

Hi there,

I'm an electrician's daughter and those tubes MUST be replaced every 6 months to avoid the above mentioned problems.  When you're in a mall, the mall managers make a point of doing this - and your grocery store - so you wil continue to shop as much as possible.   How sneaky can you get right?  I have a couple in the kitchen and I have a soft light tube in there so I'm not so overwhelmed when I'm in there.

I do however replace them twice a year to avoid any problems - and that's what any electrician will tell you b/c of the gases the tubes emit will give problems.

Bye for now - Bad Kitty

( I do have a hairy all black cat - I'll upload her one day)

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