Fluroescent lamp sptecra - can you get daylight with LED's too ?

Capt'n Midnight

http://www.salsburg.com/lightcolor/lightcolor.html - specta of various bulbs

you can get full spectrum or natural fluorescent tubes , IIRC they are slightly less efficient and far more costly than the normal ones.

is it possible to use normal fluorescents and replace the missing colour components with ultrabrite LED's or use the UV to illuminate other flourescent surfaces ? so you get the full spectrum effect with less cost and less electricity ?

probe

Capt'n Midnight wrote: »

http://www.salsburg.com/lightcolor/lightcolor.html - specta of various bulbs

you can get full spectrum or natural fluorescent tubes , IIRC they are slightly less efficient and far more costly than the normal ones.

is it possible to use normal fluorescents and replace the missing colour components with ultrabrite LED's or use the UV to illuminate other flourescent surfaces ? so you get the full spectrum effect with less cost and less electricity ?

I doubt if hairdressing salons and Hermes or Cartier botiques will be using LED lighting anytime soon, but does colour rendition matter much for street lighting at night? LED street lights use about 16% of the energy of conventional street lights. AFAIK there isn't one LED street light (ie public street lighting in ESB lingo) in Ireland. One has to ask why?

.probe

Carawaystick

Low pressure sodium ~200 lumens per watt
cree have ultrabrite leds 131 lumens per watt.

200 is not 16% of 131 in any numerical base.

Capt'n Midnight

low pressure sodium FTW all right
also means astromomers can filter out the light easily as it's nearly monochromatic

only disadvantage is that red fire engines appear black, but nowadays they have big fluorescent stripes on them so not a biggie IMHO

The point is not to use LED instead of fluorescent as that would have a large capital cost. the idea is to use them to compliment the missing wavelengths , filling in the gaps as it were

probe

Carawaystick wrote: »

Low pressure sodium ~200 lumens per watt
cree have ultrabrite leds 131 lumens per watt.

200 is not 16% of 131 in any numerical base.

http://www.economist.com/business/displaystory.cfm?story_id=10214726

.probe

Carawaystick

White LED's are usually 2 or 3 colors, the actual led is often uv and 2 or 3 flourescent chemicals are used, a blue and a yellow often.

Fluorescent lights usually have more types of phosfor giving better colour rendition, but it's not great yet. there is a measure called Colour Rendition Index to quantify this.

Low pressure Sodium lamps are monochromatic, and no colours can be seen under it. this is the source of it's efficiency, and why these are used for streetlights.
Probe, the economist only states that leds are better than incandescent bulbs. Incandescent lamps havn't been used for streetlighting in most places for a long time.
and leds are still not better than sodium.

probe

Carawaystick wrote: »

White LED's are usually 2 or 3 colors, the actual led is often uv and 2 or 3 flourescent chemicals are used, a blue and a yellow often.

Fluorescent lights usually have more types of phosfor giving better colour rendition, but it's not great yet. there is a measure called Colour Rendition Index to quantify this.

Low pressure Sodium lamps are monochromatic, and no colours can be seen under it. this is the source of it's efficiency, and why these are used for streetlights.
Probe, the economist only states that leds are better than incandescent bulbs. Incandescent lamps havn't been used for streetlighting in most places for a long time.
and leds are still not better than sodium.

I don't know anywhere using low pressure sodium street lamps (yellow light) except some parts of Ireland and GB. The street lights in my area are white - less traffic accidents and better visual recognition and it looks better when one is walking around.

What was the Economist journo meaning when he referred to "incandescent" light - did he use it as a generic term for non-LED sources?

I would doubt if a city is going to invest in LED street lighting without energy saving and or better colour rendition etc - and thus better safety - and probably both.

.probe

Carawaystick

I've seen low pressure sodium streetlights in France, Luxemburg and Germany, this year.

This doesn't back up your safety argument
more deaths per car and per million pop that britain.
http://www.finfacts.com/irelandbusinessnews/uploads/oecdfactbook12006m06.gif

High pressure sodium lamps can only achieve up to about 150 lumens per watt,
The best Led I can find is 131 lumens per watt.
http://www.cree.com/press/press_detail.asp?i=1150834953712

Why would you want to use less energy efficient lights? that's not very green.

Incandescent means emiting radiation as a result of a body's temperature, usually referring to the tungsten filament of an incandescent bulb.
If the Economist aren't going to use words to mean what they mean, it renders the entire article useless.

Also non-incandescent bulbs use fairly nasty chemicals in their manufacture, lots of mercury and arsenic and other bad heavy metals.

probe

I came across some LED display lighting in a boutique environment today. The focus of the pic isn't 100% because I was taking it through two layers of glass - but the LED lamp which appeared to be halogen fitting compatible did the job.

http://der.probe.googlepages.com/led.jpg

.probe