Tim Mitchell wrote:
In article , Ian
Stirling writes
Tim Mitchell wrote:
In article , Ian
Stirling writes

There exist 'warm white' LEDs, which don't do this.

really, what manufacturer?

I thought that LEDs by their nature only produce a narrow spectrum of
light.

They do.
It's just that some come with a fluorescant material with a wider spectrum.
Luxeon "Warm White" LEDs.
LEDs and fluorescants are basically similar - one uses blue, the other
uses UV to excite a mix of phosphor.
It's just that with the LED, the basic colour can be used as part of the light,
if desired.

Right, I have seen the luxeon ones. The light quality is still not that
great, I wouldn't want to use one as a work light as the OP wanted (even
if you could get enough to make it bright enough). The colour
temperature is quite variable from device to device, and also within the
beam of each LED.

The "warm white" variant?
It's distinctly different, and really does look "warm white".
The normal one is slightly more efficient, and is more variable.