On Thu, 29 Aug 2019 01:31:58 +0100, Rod Speed wrote:



"Commander Kinsey" wrote in message
news
On Wed, 28 Aug 2019 21:09:53 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news On Wed, 28 Aug 2019 05:29:07 +0100, Rod Speed
wrote:



"Commander Kinsey" wrote in message
news On Tue, 27 Aug 2019 22:38:57 +0100, Max Demian

wrote:

On 27/08/2019 17:25, Commander Kinsey wrote:
On Tue, 27 Aug 2019 17:13:18 +0100, Colonel Edmund J. Burke
wrote:

On 8/27/2019 9:03 AM, Commander Kinsey wrote:
Why is hi-vis clothing easier to see? Whats so special about the
colour?

Color, you ignorant limey.

So why isn't red, yellow, etc as easy to see? If you wear a bright
red
tshirt, you aren't as visible as wearing a hi-vis jacket. Does it
convert all the wavelengths into one or something?

It's fluorescent. It converts ultraviolet (especially prevalent in
the
dusk) into visible light.

I never realised this - there's more UV at dusk?

Yep, because the sunlight is going thru a lot more air
and dust etc in the air and UV gets thru that better
than the longer wavelength light. Thats why sunsets
are red, the red light is reflected off the crap in the air.

Isn't it to do with diffraction and refraction?

Yes but thats just different words for the same thing.

No,

Yep.

No.
Diffraction is light encountering an obstacle, like the edge of a planet: https://en.wikipedia.org/wiki/Diffraction
Refraction is light encountering a different medium, like going from the air into a lake: https://en.wikipedia.org/wiki/Refraction

one is bending round corners, eg long wave radio goes further as it can go
over mountains.

Thats not what is involved in there being more UV at sunset.

The other is bending when it goes into another medium, eg shining a torch
into water.

Thats not what is involved in there being more UV at sunset.

One bends high frequencies more, the other bends low frequencies more..

More UV at sunset isnt about bending.

You said above: "Thats why sunsets are red, the red light is reflected off the crap in the air."
But er.... we see sunsets as red, which means the red end of the spectrum must be reaching our eyes more than the blue end.

Or just the same amount, and less visible light?

Less of the long wavelength red end of the spectrum, anyway.

Sunsets are orange.

Nope, red and red is adjacent to orange in the spectrum anyway.

Near enough. My point was there is more of the long wavelength end of the
spectrum at sunset.

Not when talking about what ends up at the hi vis vest.

How would that be different from what ends up at your eye when looking at a sunset?

You were incorrect!

Nope, I never am.

[falls off chair]

I guess it's to do with diffraction of sunlight at the horizon?

More the much longer amount of air in the path between
the sun and you.

Presumably mainly available in certain colours.

Why are they always yellow or green?

They arent normally green and plenty are orange/reddish.

Almost every one I see nowadays is yellow.

Then you need to get out more.

I have no desire to see more health and softy bull****.

It isnt H&S bull****.

That's what hivis is all about - ****ing safety.

A google image search shows 75% yellow and 25% orange,

Its nothing like a representative sample of whats seen in the real world.

A google search is very representative.

Google image results arent.

Same coding.

although I can't remember the last time I saw an orange.

Then you need to get out more. It varys by industry too. some
like the railways have their own colors for various reasons.

Ah, I do remember orange at a level crossing.

Yeah, thats the most obvious example.

Why do railways need different colours?