Dave Plowman wrote in message ...
In article ,
N. Thornton wrote:

I would not recommend anything as high colour temp as that for
domestic use. 4500K is going to look terrible, and 4700K a shade
worse.

Depends whether you want to retain the accuracy of the colours on your
monitor - although this depends on what colour temperature it's designed
or set up for.

Tubes like that look terrible under all conditions. Cool white is the
tube that gave fluorescents such a bad name, and 4500K is quite
similar to cool white, being nearly as nasty. The only exception I've
found is with extremely low powers, like 2w, which give an icy moonlit
nightlighting effect.

3500K shouldnt distort the eye's view of 6000K monitor colours - but
setting a monitor to 9000K is both colour distortion and not very
pleasant to work with. I've never really understood why its a popular
setting. Things look so much better at more sensible colour temps.


Regards, NT

In article ,
N. Thornton wrote:
Depends whether you want to retain the accuracy of the colours on your
monitor - although this depends on what colour temperature it's
designed or set up for.

Tubes like that look terrible under all conditions. Cool white is the
tube that gave fluorescents such a bad name, and 4500K is quite
similar to cool white, being nearly as nasty. The only exception I've
found is with extremely low powers, like 2w, which give an icy moonlit
nightlighting effect.

Well, since there are tubes that mimic daylight, perhaps you're actually
Dracula? ;-)

3500K shouldnt distort the eye's view of 6000K monitor colours - but
setting a monitor to 9000K is both colour distortion and not very
pleasant to work with. I've never really understood why its a popular
setting. Things look so much better at more sensible colour temps.

Genuine daylight tubes are excellent for work environments, IMHO, or where
colour rendering is important. But don't confuse them with the nasty
'white' things supplied with a cheap fitting.
Of course, domestically, you'll often need a better match to tungsten for
pleasant night time lighting, but that's a different ball game.

--
*Women like silent men; they think they're listening.

Dave Plowman London SW 12
RIP Acorn

In article ,
(N. Thornton) writes:
Dave Plowman wrote in message ...
In article ,
N. Thornton wrote:

I would not recommend anything as high colour temp as that for
domestic use. 4500K is going to look terrible, and 4700K a shade
worse.

Depends whether you want to retain the accuracy of the colours on your
monitor - although this depends on what colour temperature it's designed
or set up for.

Tubes like that look terrible under all conditions. Cool white is the
tube that gave fluorescents such a bad name, and 4500K is quite
similar to cool white, being nearly as nasty. The only exception I've
found is with extremely low powers, like 2w, which give an icy moonlit
nightlighting effect.

A lesson in colour temperatures might be handy here...
Your eyes and brain were designed to work with natural sunlight.
Sunlight has a very wide range of colour temperatures and intensities.
The midday summer sun can be 6000-8000K and very bright. Conversely,
sunset can be less than 2500K and very dark compared to midday summer
sun. However you can still see colours fine in both these environments
as your eyes and brain are evolved to work over that range.

Now what screws things up is if the colour temperature is way out of
range for the light level (lumens). Artificial lighting levels people
use in their houses are actually not a lot brighter than sunset, so
the colour temperature most appropriate is around that of a filament
lamp at 2700K. (You might argue that given a filament lamp is 2700K,
people have chosen lighting levels so that looks 'right'.) This is
also the colour temperature of most compact fluorescent retrofits so
they match filament lamps and your expectations of colour temperature
of artificial lighting.

For lighting during the daytime, you will expect higher light level,
e.g. in an office. To match a higher light level, you would also
expect a higher colour temperature. This is why offices normally use
3500K colour temperature lamps. If you intend to light a room in
your house particularly brightly (maybe the kitchen or a workshop
where you do intricate work), you might prefer 3500K lighting there,
but it will seem a bit strange initially when you walk in to it in
the evening, although you will adjust to the higher lighting level
and colour temperature in a matter of seconds.

Now the very high colour temperature lamps (~5000K and up) will look
perfectly OK if you fit enough of them that you get up to midday
summer sun lighting levels. That probably means completely covering
the ceiling with the fittings. Remember what happens if you take a
sheet of white paper out into the summer sun -- you have to squint
to read it the light level is so bright, and even after time to
adjust to the lighting level, it won't be comfortable reading it.
Now you will have to get your artificial lighting up to that same
uncomfortable level before these very high colour temperature lamps
will feel right. Why you would want to do this I can't imagine.

Another area confused with colour temperature is the nature of the
spectrum a lamp emits -- continuous at one extreme and a few discrete
lines at the other. This is completely unrelated to colour temperature,
but unfortunately the lighting industry marketing people confuse the
issue for using terms which imply a continuous spectrum when they
really mean high colour temperature. The two properties are not
related. Descrete line sources, or sources which are continuous but
are not even or have some holes/peaks in the range can cause colours
to be washed out, simply because they happen to be missing some of
the components a particular pigment responds to, of have an over-
abundance in some part of the spectrum. Generally your eyes are
quite forgiving of descrete line light sources, providing there are
enough lines covering the visible spectum and they are not too badly
matched. TV cameras and anything else which splits an image up into
colour components and reassembles it at the other end can be a lot
less forgiving though.

--
Andrew Gabriel

In article ,
Andrew Gabriel wrote:
Another area confused with colour temperature is the nature of the
spectrum a lamp emits -- continuous at one extreme and a few discrete
lines at the other. This is completely unrelated to colour temperature,
but unfortunately the lighting industry marketing people confuse the
issue for using terms which imply a continuous spectrum when they
really mean high colour temperature. The two properties are not
related. Descrete line sources, or sources which are continuous but
are not even or have some holes/peaks in the range can cause colours
to be washed out, simply because they happen to be missing some of
the components a particular pigment responds to, of have an over-
abundance in some part of the spectrum. Generally your eyes are
quite forgiving of descrete line light sources, providing there are
enough lines covering the visible spectum and they are not too badly
matched. TV cameras and anything else which splits an image up into
colour components and reassembles it at the other end can be a lot
less forgiving though.

You've put it far better than I ever could, Andrew, - thanks. Continuous
even spectrum lighting is essential if you need to match colours - or
indeed even expect them to look 'right'. And with low level lighting as
you might want while using a monitor or viewing TV, it's equally as
important if you wish to see the colours as intended. Of course, with TV,
a vast proportion of the public don't care - the brighter and more
'primary' the colours on their screen the happier they are - regardless.

--
* What do they call a coffee break at the Lipton Tea Company? *

Dave Plowman London SW 12
RIP Acorn

Dave Plowman wrote in message ...
In article ,
N. Thornton wrote:

Tubes like that look terrible under all conditions. Cool white is the
tube that gave fluorescents such a bad name, and 4500K is quite
similar to cool white, being nearly as nasty. The only exception I've
found is with extremely low powers, like 2w, which give an icy moonlit
nightlighting effect.

Well, since there are tubes that mimic daylight, perhaps you're actually
Dracula? ;-)

oh $%&£! the secret's out.


Regards, NT

Dave Plowman wrote in message ...
In article ,
Andrew Gabriel wrote:
Another area confused with colour temperature is the nature of the
spectrum a lamp emits -- continuous at one extreme and a few discrete
lines at the other. This is completely unrelated to colour temperature,
but unfortunately the lighting industry marketing people confuse the
issue for using terms which imply a continuous spectrum when they
really mean high colour temperature. The two properties are not
related. Descrete line sources, or sources which are continuous but
are not even or have some holes/peaks in the range can cause colours
to be washed out, simply because they happen to be missing some of
the components a particular pigment responds to, of have an over-
abundance in some part of the spectrum. Generally your eyes are
quite forgiving of descrete line light sources, providing there are
enough lines covering the visible spectum and they are not too badly
matched. TV cameras and anything else which splits an image up into
colour components and reassembles it at the other end can be a lot
less forgiving though.


You've put it far better than I ever could, Andrew, - thanks. Continuous
even spectrum lighting is essential if you need to match colours - or
indeed even expect them to look 'right'. And with low level lighting as
you might want while using a monitor or viewing TV, it's equally as
important if you wish to see the colours as intended.


Hang on, the colours on a monitor screen are produced by the monitor
and dont depend on the ambient lighting. The eye's perception of them
depends to a limited extent on ambient lighting, but not by much. It
depends mainly just on the monitor, as the brain concentrates on this.
Hence one can use different colour temp ambient lighting without
having much effect on how the monitor is perceived.

Secondly the monitor brightness level is far removed from daylight,
thus proper perception of the monitor colour will occur if the monitor
uses a lower colour temp than daylight. Ie 9000K is well off for
correct perception. Even 6000K is much too high.

Then there's the question of preference... I prefer a low colour temp
display, I find it much more comfortable to work with, and the colours
overall appear richer and warmer. And why not.

And thanks to Andrew Gabriel for a good piece there.


Regards, NT

"N. Thornton" wrote in message
...
Dave Plowman wrote in message
...
In article ,
N. Thornton wrote:

Tubes like that look terrible under all conditions. Cool white is the
tube that gave fluorescents such a bad name, and 4500K is quite
similar to cool white, being nearly as nasty. The only exception I've
found is with extremely low powers, like 2w, which give an icy moonlit
nightlighting effect.

Well, since there are tubes that mimic daylight, perhaps you're actually
Dracula? ;-)

oh $%&£! the secret's out.

Did you see Rory Bremner's "I'm a calamity, get me out of here"? The one
where he's doing Conservative leaders in the jungle and he had Michael
Howard sleeping during the day hanging upside down from a tree cocooned in a
sleeping bag. Very funny.

Suzanne

In article ,
N. Thornton wrote:
Hang on, the colours on a monitor screen are produced by the monitor
and dont depend on the ambient lighting. The eye's perception of them
depends to a limited extent on ambient lighting, but not by much.

I'm afraid they do. If you use dimmed tungsten as a background, the brain
adjusts to that. Might not be the case if your screen was so big as to be
your full field of view, but this isn't of much use for a computer monitor.

It depends mainly just on the monitor, as the brain concentrates on
this. Hence one can use different colour temp ambient lighting without
having much effect on how the monitor is perceived.

It's been known from the early days of colour TV that the control rooms
where the cameras are adjusted must have the background lighting of the
same colour temperature as the monitors. Of course, for just watching TV
at home, you can have what suits you, but I'm talking about ideal viewing
conditions here - as might well apply at home if you're doing graphics
work on your computer.

Secondly the monitor brightness level is far removed from daylight,
thus proper perception of the monitor colour will occur if the monitor
uses a lower colour temp than daylight. Ie 9000K is well off for
correct perception. Even 6000K is much too high.

The colour temperature of daylight doesn't necessarily change with
brightness - that daylight might well find its way into a room via a white
reflective area - say a wall. In the middle of a field, it will, because
as the day changes both the level and colour temperature change, but you
don't use a monitor in a field.

Then there's the question of preference... I prefer a low colour temp
display, I find it much more comfortable to work with, and the colours
overall appear richer and warmer. And why not.

I'm not knocking individual preferences - just saying how it should be
done if you wish pro results on graphics, etc.

And thanks to Andrew Gabriel for a good piece there.

Absolutely.

--
*Time is what keeps everything from happening at once.

Dave Plowman London SW 12
RIP Acorn

"Suz" wrote in message . ..
"N. Thornton" wrote in message
...
Dave Plowman wrote in message

Well, since there are tubes that mimic daylight, perhaps you're actually
Dracula? ;-)

oh $%&£! the secret's out.

Did you see Rory Bremner's "I'm a calamity, get me out of here"? The one
where he's doing Conservative leaders in the jungle and he had Michael
Howard sleeping during the day hanging upside down from a tree cocooned in a
sleeping bag. Very funny.

Suzanne

lol.

In message , Dave Plowman
writes
The colour temperature of daylight doesn't necessarily change with
brightness - that daylight might well find its way into a room via a white
reflective area - say a wall.

Maybe I've misunderstood what you're trying to say here but, but the
daylight reflected off a *white* wall will have the same colour
temperature as the actual daylight.

--
bof at bof dot me dot uk

In article ,
bof wrote:
The colour temperature of daylight doesn't necessarily change with
brightness - that daylight might well find its way into a room via a
white reflective area - say a wall.

Maybe I've misunderstood what you're trying to say here but, but the
daylight reflected off a *white* wall will have the same colour
temperature as the actual daylight.

Yup. But others have said that the perceived colour temperature varies
with brightness. Personally, I'm not so sure. We know that as it gets
dark, the colour temperature drops along with the brightness - although
this is far more marked on a sunny day.

--
*Suicidal twin kills sister by mistake.

Dave Plowman London SW 12
RIP Acorn