"Andrew Gabriel" wrote in message
...
"Andy Champ" wrote in message
. uk...
Lumme that stirred it up - and it was only the RF pollution I mentioned!

A couple of points guys on that long discussion:

Colour Temperature - the CFL is a lot closer to daylight for our
3-colour-sensor eyes than the old incandescent. I daresay people said

Daylight covers a wide range, from dawn (2100K), through to midday
(5600K), through to just before twilight (2100K). Incandescent (2700K)
is a damn good match for daylight at the time we need to start enhancing
light levels for our own comfort at home. What we in effect do in our
homes
is stretch out the early evening period before twilight for which daylight
is 2700K way into the evening/night, both at the colour temperature and
comenserate lumen level (illumination level).

Office and other workplaces generally have more demanding lighting
requirements to keep us working more optimally rather than dozing off.
Hence office lighting tends to operate at 3500K and higher lumen
levels, mimiking a natural daytime period even further from night time
than we chose to do at home.

For a natural feel, it is reasonably important that the colour
temperature and lumen level are reasonably well synchronised. If you
turn on a 5600K fluorescent in the evening, it will look horribly blue,
but this is because the lumen level is completely wrong. Unfortunately,
to get the lumen level up to midday levels, you are going to have to
completely cover your ceiling with fluorescent fittings. If you do
this, that colour temperature will then appear natural at that lumen
level. (This effect is named after someone, but I've forgotten the name,
and a google search was no help.)

that the incandescent was too blue, and lamplight was better... And no,
I
wouldn't want to mix paint under a CFL. Nor choose it.

You probably want to do that under the conditions you are most often
going to view it. In a bedroom for example, in most cases, that's not
going to be with daylight streaming in the windows.

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

All of what you say is quite true, but the colour temperature must be taken
in conjunction with the CRI, which for a CFL is less than the ideal of 95 -
100, by quite a margin. It is this shortcoming, rather than the colour
temperature, which gives rise to the 'sick' quality of the light, no matter
how close it is to matching daylight, at any time of the day, in terms of
colour temperature.

LED lighting suffers similarly, because again, like the individual phosphors
in the tricolour mix used to coat the CFL's discharge tube, each individual
LED colour used, has a narrow spectrum of output, giving rise to an overall
'peaky' spectrum, rather than the much 'smoother' ones of daylight and
incandescent light.

Arfa