CFLs and LEDs

And you’re surprised?

Tim

LEDs are sorted by colour temperature. And you can have as much "brightness" as you can stand.

For example, a 9000K LED is "too blue" for me.

A 2500K LED is "too reddish". Some of the "warm" LED bulbs, have actually had a couple red LEDs inside the bulb, to give it the hint of a reddish tone (Philips).

The LED you got might have been 4000K or 4500K. These are all nominally white LEDs (white colour distribution), but the colour temperature is shifted to emulate a particular kind of existing light.

Fluorescents also received some phosphor work, and there are ones with a Daylight rating, which will be brighter like your LEDs. Making phosphors is hard, because the material must be cheap to make in bulk. You cannot go overboard on the rare earth materials.

Some people select particular light types, to counter winter depression. So it seems like it is "always summer" in the house.

At some stores here, the LEDs are on display, so the customers can make better selections while at the store, and not regret what they bought later.

When I bought a particular LED bulb years ago, on the outside of the package it said "this bulb is NOT yellow". When I compared the light emitted, to an existing LED in the house, well, the light was yellow. You can't make this stuff up :-) The plastic on the bulb appeared yellow... and shocker, so was the light that came out :-)

"Philips bulb with the remote phosphor panels (the yellow bit)"

Paul

Yes because CFLs are supposed to be very efficient. That's what they told us...

snipped-for-privacy@f2s.com snipped-for-privacy@f2s.com wrote

They said that back in the days when CFLs were being spruiked.

They never said that they were very efficient compared with LEDs

CFLs were only efficient compared to tungsten. They were a transient abomination whose efficiency was surpassed by LEDs *years* ago.

Tim

Less than 10 years ago. CFLs had been around for a lot longer.

There were a handful of research grade LEDs made that could achieve extremely high efficacy in the lab on a near infinite heat sink. But they were still a very long way away from being consumer products.

This is a puff piece for Cree who were at the time world leaders:

Do they still exhibit the slowly getting brighter issue of cfls. Obviously its mostly visitors that use the lights, but still. I was also wondering what to do about a thorne fitting of two tubes with two 40 watt tubes in it. It would be nice to use LED tube replacements, but I seem to only see thin ones. Also I did have a notion it might be fun to hide a small device like the Alexa switched socket inside the device to turn it on and off with, but it is actually too big. You really need a module for that I think. Brian

I remember when they first appeared noting with my failing sight that it seemed a grainy light, almost speckled.

My feeling is that some of the most efficient phosphors are not very daylight like at all, and have big holeds in the visual spectrum. Brian

When I had a video camera here and could see, I remember noting that all faces were yellow with the gas tube technology, and you needed at least some tungsten technology as well to make people look more like humans and not aliens. You could to some extent move camera controls to make it see better but when you went outside it looked awful. Brian

There are plenty of small ALEXA capable modules on Amazon. I have a couple for my kitchen down lights.

Dave

Yes, around that time I became happy with 13W LEDs as true "100W equivalent" replacements, that didn't burn out in short order.

Johnny B Good can finally buy his 200 lm/W LEDs, provided 60W is enough and it doesn't need to be dimmable or use bayonet fitting ...

We used daylight-colour CFLs (*) in our last house and the colour *looked* pretty good - occasionally I've forgotten that the light was on, thinking it was daylight coming in through the window. There was a *very* pale green cast when seen by eye, but this was only apparent at night, maybe when the CFL was the only source of light without any daylight from outside. But a camera that was white-balanced to "daylight" (probably around 6000K) saw the CFLs as being a bit orange. Shows how the sensitivity of the eye and of a camera can differ.

We've still got those CFLs in the garage in case we ever need them, but we've gone over to Philips Hue LED bulbs - mostly arrays of GU10 because our new house had already been wired for GU10s in the kitchen and bedrooms. I removed lots of tungsten GU10s which must have used a lot of power, and replaced them with either Philips Hue where we wanted control over colour/brightness or normal LED of either "daylight" or "tungsten" colour.

Interesting , Brian, that CFLs looked "grainy" and "speckled". That almost suggests coherent light that you'd get with a laser

(*) Supposedly designed to give high colour rendition index so as to compare well with natural daylight.

Probably the CFLs were designed to look "warm" so as to match tungsten or "warm white" fluorescent tubes. Interesting that CFLs looked *more* yellow than with tungsten light, via the video camera. Once you'd white-balanced the camera for those CFLs and/or tungsten lights, daylight would look very blue. That was one of the perils with video cameras that only had a black-and-white viewfinder: you could not see any colour cast. When I was filming my sister's wedding, I'd manually balanced (*) the camera for the indoor lighting and then went outside to film some guests: until I remembered, the outside scenes were very blue. With a colour viewfinder, I'd have noticed instantly.

(*) The auto white-balance that you get on a lot of modern cameras works surprisingly well, but it can lead to rather colourless photos outdoors, so I tend to white-balance off a sheet of paper and then keep that setting (if the lighting is non-standard) or else use one of the preset colour balances - especially with my DSLR which suffers badly if left on auto WB when used outdoors.

CFLs were very much a compromise but LEDs are, even now, far from perfect in some applications. Most of our lights are LED but we have a few Halogens, mainly for detailed work eg Senior Management does a lot of cross stitch etc and I’ve yet to find a suitable LED light for her work light. Ditto my work bench where I do electronics etc.

We have some wall lights, which we really like, in two rooms, and it took ages to find suitable LED bulbs for those ( golf ball dimmable which are bright enough on full). I’d bought a huge stock of tungsten bulbs just in case!

I had a similar problem finding suitable LED equivalents for some other fittings which used 2x 40w halogens. The early ones which claimed to be

I’ve replaced most of the tubes in the garage with LED tubes - one left to do. They are great, far brighter. I must do the remaining one!

Brian Gaff snipped-for-privacy@gmail.com wrote

Dunno, ever got any new ones since LEDs became viable.

Some of the Philips Hue bulbs arent thin. More of a cone shape than the original incandescent bulbs, but work fine where the normal incandescent bulbs were used.

Makes more sense to use Philips Hue smart bulbs.

Nope, smart bulbs eliminate the need for any module.

it could be anything. It's most probably 2700K. Any respectable LED lamp outputs more than typical CFL, which had misleading output equivalence claims.

no, lighting LEDs are cool white, 2700K are made by colouring the layer over the semiconductor light yellow.

CCT and efficacy in fluorescents are 2 separate things. In LEDs, warm white are necessarily a bit lower efficacy.

They normally select regular RGB white marketed as continuous spectrum.

usual marketing then

I like 4000K

Bill

CFLs always overstated their luminous equivalence to filament bulbs whereas most LED bulbs are basically honest. It caught me out with one I put in my parents bathroom (to be instant on unlike ageing CFL) being far too bright!

That yellow colour is not a passive filter it is a red/yellow/green emitting phosphor that is excited by the incredibly bright blue LED behind it. The mixture produces what we perceive as white light. See:

CFLs have an incredibly bright mercury green line augmented by a red phosphor. It looks approximately white to humans but not to film.

Unclear that it makes any difference though. The blue light from a standard white LED and its intensity matters much more.

If you were a plant then the blue + red + nearIR LED matrix lamps are all the rage now. No point shining green light at a green plant!

Odd. It is quite hard to make a super bright yellow LED and there isn't much call for them. I find the claim less than credible. The phosphor always looks a some shade of yellow in daylight.

I asume you mean efficiency and not efficacy, quite different meanings.