Butchers have special fluorotubes withe extra red to make meat look
better. Ordinary fluoro tube phosphors the light with the higher green
content makes the meat look past its best and unappetising.
>> You can get LED lamps for any colour temperature these days even down
>> to 2700K although I have had some marked 2700 that were more like
>> 3500. You can't complain about the brightness of the latest generation
>> - they leave CFLs in the dark for lumens per watt now and start
>> instantly at full brightness which is very useful on stairs.
>
> I do believe the best way to get good colour rendition from white led's,
> is to make the white up from RGB led's.
> I believe the white led's produce ultra violet light from the die, then
> convert it to white using a phosphor lens or something,
It is actually a hard blue light and the broadband phosphor is amber
yellow bordering on red. The final result isn't too bad these days once
there is a diffuser around it. How much red determines the effective
colour temperature. Early ones tended to have obvious coloured fringes
at edge of beam if they were used in water clear packaging.
> but either a single RGB led, or a selection of individual red, green and
> blue led's close together seem to produce a much nicer white, and you
> can easilly adjust it to your taste of white by varying the brightness
> of the individual colours current.
Very much more expensive to do and you have a nightmare mixing the
colours properly in the beam. The new generation of stage spotlights are
done this way and can mix any colour to order. White ones are still a
lot cheaper and brighter if you only want pure white light though.
They do exist in consumer products too but are generally more expensive
and less powerful than the highly optimised warm white LEDs.
http://www.amazon.co.uk/Changing-Long-Life-Lamp-Company/dp/B0058G6YF6/ref=pd_sim_light_2
(not an endorsement I have never tried one)
--
Regards,
Martin Brown