http://wiki.diyfaq.org.uk/index.php?title=Rewiring_Tips
has
Kitchen worktop lighting
twice...

and what does the K stand for in
Fluorescent tube types

3500K cant mean 3500 KW can it, as in a 100watt bulb...

--

[george]

~ [g] ~
~ ~
~ 07970 378 572 ~
~ www.dicegeorge.com ~
~ (c)2008 ~
~ ~

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "George \(dicegeorge\)"
saying something like:

and what does the K stand for in
Fluorescent tube types

3500K

Colour temperature.
--
Dave
GS850x2 XS650 SE6a

"It's a moron working with power tools.
How much more suspenseful can you get?"
- House

George (dicegeorge) wrote:
http://wiki.diyfaq.org.uk/index.php?title=Rewiring_Tips
has
Kitchen worktop lighting
twice...

So it does... different words the second time as well ;-)

and what does the K stand for in

Kelvin.

Fluorescent tube types

3500K cant mean 3500 KW can it, as in a 100watt bulb...

No its a way of describing colour temperature based on the frequency of
radiation you would get from a perfect black body radiator. (same
concept as "red hot, white hot" etc)

http://www.mediacollege.com/lighting...mperature.html

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Wed, 1 Oct 2008 00:30:53 +0100, "George \(dicegeorge\)"
wrote:

http://wiki.diyfaq.org.uk/index.php?title=Rewiring_Tips
has
Kitchen worktop lighting
twice...

and what does the K stand for in
Fluorescent tube types

3500K cant mean 3500 KW can it, as in a 100watt bulb...

K stands for Kelvin as in Lord Kelvin and relates to Colour
Temperature .

In article ,
George \(dicegeorge\) wrote:
http://wiki.diyfaq.org.uk/index.php?title=Rewiring_Tips
has
Kitchen worktop lighting
twice...

and what does the K stand for in
Fluorescent tube types

3500K cant mean 3500 KW can it, as in a 100watt bulb...

K stands for Kelvin - the unit of colour temperature. Which in practice
means the colour of the light. Lower numbers tend to the red end of the
spectrum, higher, the blue.

Approx 6500K is daylight - 3500K is warm white.

--
*I took an IQ test and the results were negative.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
"Dave Plowman (News)" writes:
In article ,
George \(dicegeorge\) wrote:
http://wiki.diyfaq.org.uk/index.php?title=Rewiring_Tips
has
Kitchen worktop lighting
twice...

and what does the K stand for in
Fluorescent tube types

3500K cant mean 3500 KW can it, as in a 100watt bulb...

K stands for Kelvin - the unit of colour temperature. Which in practice
means the colour of the light. Lower numbers tend to the red end of the
spectrum, higher, the blue.

Approx 6500K is daylight - 3500K is warm white.

2700K is warm white (colour of a filament lamp).
3500K is white (used on offices, and suitable for home use
in areas of high lighting levels).
Above 3500K and below 5000K is cool white.
5400K-6500K is daylight. (Real daylight is much more complex, but
midday sun with no cloud is 5400K at lattitude of Washington DC.)

The only one which is really standardised is warm white, and
that's fixed as it has to match tungsten filament lamps so it
can be mixed with them without any mismatch.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
Andrew Gabriel wrote:
K stands for Kelvin - the unit of colour temperature. Which in practice
means the colour of the light. Lower numbers tend to the red end of the
spectrum, higher, the blue.

Approx 6500K is daylight - 3500K is warm white.

2700K is warm white (colour of a filament lamp).
3500K is white (used on offices, and suitable for home use
in areas of high lighting levels).

Ah - should have checked first.

Above 3500K and below 5000K is cool white.
5400K-6500K is daylight. (Real daylight is much more complex, but
midday sun with no cloud is 5400K at lattitude of Washington DC.)

The only one which is really standardised is warm white, and
that's fixed as it has to match tungsten filament lamps so it
can be mixed with them without any mismatch.

Which of course it rarely does.

--
*When cheese gets it's picture taken, what does it say?

Dave Plowman London SW
To e-mail, change noise into sound.

On Oct 1, 11:22*am, "Dave Plowman (News)"
wrote:
In article ,
* *Andrew Gabriel wrote:

K stands for Kelvin - the unit of colour temperature. Which in practice
means the colour of the light. Lower numbers tend to the red end of the
spectrum, higher, the blue.

Approx 6500K is daylight - 3500K is warm white.
2700K is warm white (colour of a filament lamp).
3500K is white (used on offices, and suitable for home use
in areas of high lighting levels).

Ah - should have checked first.

Above 3500K and below 5000K is cool white.
5400K-6500K is daylight. (Real daylight is much more complex, but
midday sun with no cloud is 5400K at lattitude of Washington DC.)
The only one which is really standardised is warm white, and
that's fixed as it has to match tungsten filament lamps so it
can be mixed with them without any mismatch.

Which of course it rarely does.

I thought warm white fl tubes were generally 3000K, and known for poor
CRI.


NT

On Oct 1, 12:30*am, "George \(dicegeorge\)"
wrote:
http://wiki.diyfaq.org.uk/index.php?title=Rewiring_Tips
has
Kitchen worktop lighting
twice...

and what does the K stand for in
Fluorescent tube types

3500K *cant mean 3500 KW can it, as in a 100watt bulb...

Thanks, will address those when I get a tuit.


NT

In article ,
writes:
On Oct 1, 11:22#am, "Dave Plowman (News)"
wrote:
In article ,
# #Andrew Gabriel wrote:

K stands for Kelvin - the unit of colour temperature. Which in practice
means the colour of the light. Lower numbers tend to the red end of the
spectrum, higher, the blue.

Approx 6500K is daylight - 3500K is warm white.
2700K is warm white (colour of a filament lamp).
3500K is white (used on offices, and suitable for home use
in areas of high lighting levels).

Ah - should have checked first.

Above 3500K and below 5000K is cool white.
5400K-6500K is daylight. (Real daylight is much more complex, but
midday sun with no cloud is 5400K at lattitude of Washington DC.)
The only one which is really standardised is warm white, and
that's fixed as it has to match tungsten filament lamps so it
can be mixed with them without any mismatch.

Which of course it rarely does.
I thought warm white fl tubes were generally 3000K, and known for poor
CRI.

CRI and colour temperature are not related.
All the well known/respected makes of CFL default to 2700K
quite accurately. Where I see deviations are cheap unheard
of makes (and including IKEA's). Strangely, the original
GE Genura warm white was 3000K, but GE had to change it to
2700K after too many complaints from lighting engineers
who noticed the mismatch. (There always was a separate White
one available at 3500K anyway for office lighting.)

All the well known/respected makes of CFL are CRI between
80% and 89% (a 2700K phosphor in this range has a colour
designation of 827 - first digit is CRI / 10, and second
two digits are colour temperature / 100). Again, I would
not be surprised if the cheap unheard of makes are below
80% CRI. CFL's can be made with a CRI of 90-93% (designation
927, 935, 940, etc), but I only see these available in the
types with external ballasts, and not in the CFL retrofit
products. Fluorescents can go higher than 93%, but that
requires halophosphate or other specialised phosphate tubes;
it can't be done with tri-phosphor used in compact fluorescents.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Oct 2, 2:57*am, (Andrew Gabriel) wrote:
In article ,
* * * * writes:



On Oct 1, 11:22#am, "Dave Plowman (News)"
wrote:
In article ,
# #Andrew Gabriel wrote:

K stands for Kelvin - the unit of colour temperature. Which in practice
means the colour of the light. Lower numbers tend to the red end of the
spectrum, higher, the blue.

Approx 6500K is daylight - 3500K is warm white.
2700K is warm white (colour of a filament lamp).
3500K is white (used on offices, and suitable for home use
in areas of high lighting levels).

Ah - should have checked first.

Above 3500K and below 5000K is cool white.
5400K-6500K is daylight. (Real daylight is much more complex, but
midday sun with no cloud is 5400K at lattitude of Washington DC.)
The only one which is really standardised is warm white, and
that's fixed as it has to match tungsten filament lamps so it
can be mixed with them without any mismatch.

Which of course it rarely does.
I thought warm white fl tubes were generally 3000K, and known for poor
CRI.

CRI and colour temperature are not related.
All the well known/respected makes of CFL default to 2700K
quite accurately.

I was talking about linear FLs, where the tubes marked warm white have
long been halophosphate 3000k, and invariably low CRI due to the
limitations of halophosphate technology. It is because of the poor CRI
that 3000k tubes havent been widely recommended.

CFLs are a different animal, being almost all triphosphor.


NT