"Phil Allison" wrote in message
...

"Sylvia Else"
Arfa Daily wrote:


I was given to understand that the colour of an incandescent bulb is
what humans are comfortable with, because it closely matches the colour
and spectrum of our sun.

The sun's effective temperature (the blackbody temperature that gives
approximately the same spectrum) is about 5800K, which is a lot higher
than the colour temperature of an incandescent.

** Daylight has no particular colour temp.

It varies from 11,000K on a overcasts day to less than 2000K at dawn and
dusk.

However, daylight ( like incandescent light ) has a smooth spectrum and
the human eye adjusts to the varying colour temps almost perfectly.



As an interesting example, my son-in-law is currently working on an old Mini
on my drive. The other day, it was raining, so he rigged a 'tent' over the
front, from a blue plastic tarp. When I first went under there with him,
everything had a very blue caste, as you would expect. I didn't notice any
adjustment / compensation going on in my brain, but it must have been,
because when I stepped out from under there a few minutes later, the whole
world was bright yellow. A few minutes later, all was back to normal. The
strange thing is that I don't seem to be able to adjust to CFL light in the
same way. It continues to have a sort of 'sick' quality for me. Even more
curious though, is that linear fluorescents don't seem to affect me in the
same way. I work under them all day, without issue.


Arfa