The visible part of light

 

I see lots of talk about the low power consumption of the low power lights,
but I'm missing something...

Normally, people speak about a preference for a 100W light or a 60W light,
beacuse they are concerned with the amount of light produced. Now the Watt
rating actually refers to it's consumption, and not the amount of light
produced.

I personally think the low voltage 50W bulbs give the best light, and these
9W minature flourescents the worst, but I'm speaking about the quality of
the light produced. The low voltage lights produce a full bodied pyramid of
light, whilst these 9W low power ones produce a sickly sort half hearted
light (just an opinion). Fact is though, the 9W lamp is far more attractive
for the minimal power it consumes.

My question is, what are the terms of reference to describe the amount of
light given off, (not the power consumed)?

Thanks
Jimes

 


Partial answer to my own question....

I'm looking at lumens per watt....but if the manufacturer of the light bulb
like Phillips doesn't put it on the box... can it be calculated?

Jimes




"Jimes" <k> wrote in message

 

"Jimes" <k> wrote:

No, you want total lumens, which tells you how bright a light is.  CR
(Color Rendition) is a number used with flourescents to tell you how
'good' a light is (you can somewhat determine this number from the
color temperature of the bulb).

L/W is a measure of efficiency.

 



What does 'good' mean?

I thoroughly dislike what I call the 'quality' of light from long life
bulbs, is this the same thing? They seem to give everything a dull,
yellowish tint. It's very difficult to explain :-(

Mary

 

Mary Fisher wrote:
...

Color Rendition index is a method of telling how well a light will
produce the full spectrum. Sunlight is considered the best and
everything else is compared against that standard. A low number
will mean that colors will look different than under sunlight.


Yellowish tint is a very good way to explain it. Such a light has
a low color temperature. Color temperature is based on the concept
that with an incandescent light the hotter it is, the more blue the
light it produces. Low temperature incandescent bulbs produce a
very red or orange light. Fluorescents don't work the same way but
it's possible to describe their overall light spectrum by temperature
as if they did.

Personally, the higher the color temperature, the better.

Anthony