As stated in the article CFs do not flicker in the way conventional
ballasted strip fluoros do, so any effect would have to be related to
light intesnity, colour spectrum or electromagnetic effects of the
electronic ballast. Or perhaps lack of heat output of the CFL :-)
The BBC article was more honest in saying "Low-energy bulbs 'cause
migraine'" with the 'cause migraine' bit in quotes indicating that this is
just someone else's claim rather than an established fact.
On Thu, 03 Jan 2008 11:41:19 GMT John Stumbles wrote :
Perhaps they read it in the Daily Mail . Given that millions of
people spend their entire working day in fluorescent lit offices (x
52 weeks in some deep plan and internal offices) you would expect
problems of this sort to be widely known if true. What may be true
is that trying to read with inadequate levels of light causes
migraines, but that reflects the lighting level not the technology.
On Thu, 03 Jan 2008 11:06:32 GMT someone who may be "ARWadworth"
Not really, especially as you have not reported the article title
correctly. It is, "Low-energy bulbs 'cause migraine'".
I still have a few compact fluorescent lamps that do noticeably
flicker a little when they start, though this doesn't last long.
They are all rather elderly and don't tell one about how current
In article ,
The article admits it's just someone's unsubstantiated say-so.
The industry association has correctly identified the misunderstanding.
It wasn't worth writing, or reading for that matter.
Like Volkswagen tail-lights?
The only thing I know that triggers my migraines is aspartame. One diet
cola, and that's it. Unfortunately that isn't the only trigger... just
the only one I've pinned down.
Andy Hall wrote [about migraine triggers]:
Cold around the neck: No. I race sailing dinghies, and that would
certainly be a known trigger.
Tiredness, stress: Quite likely. It's the way I live :(
Chocolate: Don't get enough to tell (calories!) but I don't think so.
Cheese: Definitely not. I've had them when eating none, and I've not
had them when I've had cheese sandwiches for lunch and toasties for tea!
Oranges: How many do you need? I've had half pint of juice with no
On Jan 3, 11:06 am, "ARWadworth"
The difference between a conventional (incandescent) bulb and a low-
energy one is that while the former emits radiation across the whole
visible portion of the electromagnetic spectrum (and thus very roughly
emulates natural light), the second one emits radiation narrowly
peaked around one (or a few) specific visible frequencies. The same
applies to traditional neon (fluorescent) lighting, sodium lights (the
yellow ones used as street lights), etc.
Now the human eye cornea is composed of a huge number of cells, each
reacting to a specific light frequency only. Under daylight, all the
cells are stimulated more or less with the same intensity; the eye is
stimulated by natural light in the natural way. More specifically, the
eye is the fit-for-purpose result of evolution based on daylight only.
Using artificial sources that only emit light at one or few specific
frequencies, only a small proportion of the cells that compose the eye
cornea are stimulated, while all the rest remain "in the dark". This
means work overload for those few cells... the results is the well-
known feeling of "tired eyes", migraines, and the similar.
This limitation of low-cost light sources and its negative
physiological effect on the eye is well known since the early fifties.
Low-cost bulbs are nothing but in-the-small evolutions of more
traditional fluorescent (neon) lights. The same sort of limitation
affects - in an even more stringent way - LED lights. Hence, it has
always been recommended (but never enough publicised) only to use
fluorescent and low-energy bulbs in passageways only or in those
ambients where people were not required to work or read.
"Environment Secretary Hilary Benn said that a voluntary agreement
with retailers would remove all conventional bulbs from the shops by
Usual governmental stupidity at work - the nanny state is at it again.
Until when there will be a market request for them - and many people
will continue to use conventional (incandescent) bulbs to work, read,
or just relax because they know the shortcomings of low-energy bulbs,
there will be conventional bulbs. They are neither dangerous nor an
energy-unsustainable technology. Only an idiot would fail to realise
that in these days of global markets they will be purchased on the
internet from sites that procure them outwith the UK... Would they be
moronic to the point of banning them with an Act of Parliament? It
will be amusing to see smugglers dealing with drugs, tobacco,
alcohol... and 60W pearl bulbs
It's OK we have it on authoriuty that only a few are going to be going
through hell whether they like it or not:
"However, the Lighting Association, which represents bulb
manufacturers, said that the latest energy-saving bulbs did not
produce a flicker.
"A small number of cases have been reported by
people who suffer from reactions to certain types of linear
Maybe some of them will like it. We will see. Maybe of the only some,
most of the only some will think it a great joke and really enjoy the
The Natural Philosopher coughed up some electrons that declared:
I had a temporary CRT at my new job while waiting for my new twin Dell
panels to turn up - forgotten how bad it used to be looking into a
Back on topic, I used to get a boat load of headaches at my second to last
job. Given that the lighting was brand new fluorescent (office refurb), and
good quality fittings, plus no-expense-spared decent LCD panels, I came to
the conclusion it was the air conditioning. Not had a problem since working
in more old-fashioned office/lab environments with opening windows.
Had a hell of a lot less diseases too (always getting colds before), but
that could equally well be no longer having to ride the germ express to
In article ,
That's correct. They work at a frequency way above the phosphor
decay rates and the eye's response rate, and somewhat above the
mercury ion's excited state decay rate, so there's no flicker.
In article ,
Actually the cone cells have wide overlapping response curves,
with the green cones covering most of the visible spectrum.
Much post-processing of the raw signals from the retina happens
in the brain. Even a monochromatic light source will trigger at
least two of the three types of cone cells throughout nearly all
the visible spectrum.
This is rubbish. There are visible effects from using narrow
line light sources, but they relate to accurate colour rendering
of coloured objects, whose absorbtion bands will result in different
apperance of colours depending on the spectural content of the light
source. In terms of discomfort, this might produce decrease contrast
on some occations. It can be used to produce enhanced contrast too
over daylight -- e.g. with higher levels of green -- which probably
require less processing in the brain to resolve the image.
No it hasn't.