I am having the house rewired. In several places (kitchen, bathroom) I am t
hinking of having inadequate pendant (?) or fluorescent tube lighting repla
ced by low power LED bulbs, flush with the ceiling. Now, LED bulbs I saw in
the past looked ghastly, like car head lights, lots of tiny spots of light
. The electrician says he will bring some samples. I get the impression the
current LED lights have a frosted cover to diffuse the LED light and the f
ixing is the same "bayonet" fixing as the GU10 bulbs. Are there any drawbac
k to these LED bulbs? They are promoted as the solution to the energy crisi
s and all other of society's ills, so I wonder how long before they become
yesterday's despised fad?.
I find LEDs are rather stark compared with tungsten or CFL. We've used GU10
spotlights in two situations: three downlighter spotlights in the bathroom
ceiling; and six attached to a ceiling bar, pointing in various directions,
in the kitchen.
In both cases, the beam spread of the LED version is much narrower than for
the tungsten that they replaced, which leads to more parts of the room in
shadow, and shadows which have harder edges.
My wife has asked me to replace the ones in the bathroom with the older
tungsten bulbs, partly for the warmer colour of light. We've kept the
kitchen ones and I've got used to them now, but to begin with the lighting
was less even, despite the bulb holders being in the same positions as
CFLs (daylight colour) are great. They provide a nice diffuse light (in
large cylindrical "parchment" shades with no top and bottom) and we use them
in all the rooms (bedrooms, landing) which have pendant light fittings; in
the lounge we have a central three-bulb fitting which takes three candle
sized bulbs, and we can't get CFL bulbs that are small enough and yet bright
enough (ie 60W tungsten equivalent).
The CFLs are maybe three years old and are just beginning to show slight
signs of age: they take a minute or so to reach maximum brightness, but at
least their initial brightness is about 80% maximum, unlike early CFLs where
some manufacturers' bulbs were dangerously dim for the first few minutes.
My impression is that daylight CFLs provide better colour rendition than
daylight LEDs: they are better at rendering dark reds which look rather dull
and almost monochromatic under LEDs.
I repaced 4 halogens with 2 x 6 inch panels LED cool white 12 watt, yes
they are bright but that is what she wants (shower room ) so she can
apply make up etc, she is more than happy.
She now wants similar on the kitchen which I will do this year.
I wouldnt use them in other rooms though.
On Tuesday, February 16, 2016 at 10:45:14 PM UTC, ss wrote:
We like LEDs but won't change bulbs/strips anywhere until they die. CFLs are awful in lamps, they get very hot. Strips give dreadful colours.LEDs are like daylight. Trouble is, older 'long life' lighting lasts a long time.
The answer is not to die until they do.
Presumably CFLs get a LOT less hot that the tungsten bulb that they
replaced. I've got a 25W CFL (150W tungsten equivalent) in my study and it's
been on for a couple of hours in a shade that's a vertical cylinder about 30
cm diameter with no top and bottom. And the tube (coiled to make a unit
about the size of a tungsten light bulb) is warm but I could easily keep my
fingers on it for a minute or so.
So you think that LEDs give better colour rendition than CFLs? I took a few
test photos under daylight, daylight CFL and daylight LED (with the camera
manually white-balanced to each light source) to see which photo looks most
like real life. I'm not sure whether older strip lights (which are usually
warm-white, somewhere between the colour of tungsten and sunlight) are worse
for good colour rendition.
(daylight under 100% cloudy
fluorescent tube on camera's cloud setting to show that light is actually
Manual white balance off a piece of white card which filled the frame
My impression is that the reds (the lettering on the Radio Times and the red
panel on the packet of screws) is darker on the LED and "white" fluorescent,
and a bit more vibrant on the daylight and daylight CFL. Obviously these are
just quick tests: I've not tried to ensure that all the pictures are at the
same exposure (eg metering off 18% grey card or anything technical like
that!). Scuse the camera shake on some of them!
They are pretty much the future now with efficiency/efficacy overtaking
HPS and fluoro tubes by a fair margin.
I solved that in my kitchen by using a mixture of Philips LED spotlights
which are a bit too directional but near perfect warm white to match
existing filament lamps and a couple of warm white LED bulbs.
The current crop of LED spotlights are a bit too directional.
Whilst CFLs are serviceable they have never had decent colour rendering
and are invariably slow to reach full brightness and unwilling to start
at all in very cold conditions. Couple that with the tendency of their
control electronics to cook itself and you have it.
> CFLs are awful in lamps, they get very hot. Strips give dreadful colours.
> LEDs are like daylight. Trouble is, older 'long life' lighting lasts
a long time.
It makes sense to replace them as they fail and in the areas that get
the most use - you make the most savings that way. Replacing the one in
the loft where you almost never go makes no difference at all.
You want "warm white" LED bulbs if you want to match incandescent
lighting - the Philips and Samsung versions are the best I have found.
Some others are dreadful.
I like the 4000K - 4500K range, sometimes referred to as Daylight, sometimes
The 6000K range is too blue for me.
BTW, I don't know how they compare to Ledhut, but Ledlam has a range of
I first bought from Ledlam via Amazon but get a better price going direct.
When we first replaced our tungsten bulbs with daylight CFLs, they seemed
very blue. The difference between the bedrooms with daylight and the
bathroom with tungsten GU10s was very noticeable - tungsten looked horribly
I don't notice the difference between the two as much now. What I do like
about daylight bulbs is that the inside of my study is now the same colour
as the daylight coming through the window, whereas before the difference was
very noticeable. The only problem with that is that occasionally I forget
that I've left the light on during the day and go out with it still on!
It's quite an eye-opener to see the spectrum of a typical CFL and how many
peaks it has - not exactly black-body radiation :-) It's amazing that the
colour rendition is as good as it is with peaks and gaps like that.
I've always wondered why daylight slide film made fluorescent lights look a
horrible green colour (even when they were probably warm-white around
3500-4000K) whereas you don't get that with a digital camera. The green
emulsion of the film must have been unusually sensitive to one of the lines
in a fluorescent tube, in a way that the green pixels of a digital camera
aren't to the same extent.
The eye is easily fooled and does auto white balance.
And if you used daylight film indoor with incadescent lights it would
have a strong orange cast. Basically the film records reality.
Not at all. In fact through a curious coincidence colour panchromatic
film is actually less sensitive to green light than it should be with an
insensitive zone around 500nm which is used as a safelight.
The consequence of this was that all the old Palomar slides of deep sky
objects are coral pink and powder blue even when visually the objects
are in fact apple green from the OIII line at 501 & 496nm. The film was
completely blind to this wavelength and it wasn't until the mid 1970's
that true colour images of nebulae were obtained (front page of SciAm)
Visually it looks an oily green in the very brightest parts, but a few
of the bright planetary nebulae are a bright apple green visually but
still appear to be pink and blue on slide film.
I realise that. I was meaning, though I didn't say so explicitly, that a
slide film and a digital camera, each set to the *same* white balance (eg
daylight) will record fluorescent lights differently. On daylight film they
will be greenish, on daylight-balanced digital they will be amber if they
are warm-white tubes or reasonably neutral if they are daylight tubes.
Conversely if you use tungsten-balanced film (or an 80A blue filter and
daylight film) and a digital camera balanced for tungsten, then the
fluorescents will still have a strong green component on film but will be
either neutral or blue (depending on whether they are warm white or daylight
tubes) on digital.
So it seems that slide film is unusually sensitive (despite what you say
about "by curious coincidence colour panchromatic film is actually less
sensitive to green light than it should be") to a component in the
fluorescent tubes, whereas digital cameras aren't.
Actually, thinking about it, that's not completely true. Film is sensitive
to *some* component of fluorescents (not necessarily green light) which
*manifests itself* as a green cast - ie it triggers the green-sensitive
It's less noticeable with negative film because a green cast will probably
be corrected (either manually or automatically) at the printing stage, even
if that causes other colours then to be rendered incorrectly.
No you have fundamentally failed to grasp the effect of the digital
camera having an automatic white balance. It sees the same weird green
colour cast as the panchromatic film (only more so) in the raw data but
it is corrected before being presented as an image.
On a more advanced camera you can force it to manual white balance and
save the raw sensor data but most default to automatic white balance.
(and have done almost since the advent of digital cameras)
Yes - the very strong mercury green line at 546nm to which it is quite
sensitive away from the 500nm safelight wavelength.
I thought I was being clear enough this time by referring to
"daylight-balanced digital". I meant with the digital camera set to a
*fixed* "daylight" white balance (eg round about 5500K for sunlight) and
*not* with auto white-balance enabled.
Auto-white balance, either in a digital camera or of the printing stage with
negative film, can correct a multitude of sins, so all bets are off if
You do realise there is no such uniform thing as daylight? The colour
temperature of that varies according to time of day, time of year, part of
the world and weather conditions. And likely more I've missed out.
*Some people are only alive because it is illegal to kill.
Dave Plowman email@example.com London SW
Yes, I meant the camera/film settings rather than the colour of the light. I
think direct sun in a mostly blue sky has a colour temperature of *around*
5500K (subject to time of day etc variations). And it is this colour
temperature (AFAIK) that "daylight" colour slide film and the "sunlight"
white balance setting of a digital camera are balanced for.
Likewise tungsten film and the "incandescent" setting of a digital camera
are balanced for tungsten light which is about 2500-3000K depending on
whether it's normal household bulbs or Photoflood photographic lights.
My digital camera has a variety of different "fluorescent" white balance
settings for warm-white, white, daylight, low/high-pressure sodium and
mercury lights (I know sodium and mercury are discharge without fluorescent
phosphors, but the camera lumps them all together). None of these settings,
when used with sunlight, gives a pink cast which would be necessary to
counter a green cast from fluorescent lights; instead all these settings
seem to give varying proportions of amber and blue, which seems to suggest
that the digital sensor is less affected by the green line in fluorescent
tubes and therefore does not have settings that correct for it.
I do realise that light from a 100% cloudy sky is bluer (8000K or beyond),
and that shade could be all sorts of weird colours depending on what the
light is reflecting from (grass, buildings of various colours, people's
clothes etc) but is predominantly bluer than direct sunlight because of the
blue from the sky.
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