On Mon, 13 Feb 2017 07:51:37 -0000, Chris Hogg wrote:

On Sun, 12 Feb 2017 22:55:18 -0000, "James Wilkinson Sword"
wrote:

On Sun, 12 Feb 2017 22:52:01 -0000, Chris Hogg wrote:

On Sun, 12 Feb 2017 16:54:35 +0000, Andy Bennet
wrote:

On 12/02/2017 13:32, dave wrote:
Is 80 gms printer paper getting thinner - or am I just imagining it!
Certainly getting more expensive


I think they are adding a lot of depleted uranium to the paper now to
get rid of it.

chuckle
I know a lot of paper these days fluoresces under UV light, but that's
not from its uranium content! (They actually add fluorescent dyes to
the mix to make it appear extra white,

Wouldn't that make it extra purple?

See https://en.wikipedia.org/wiki/Optical_brightener

Most 'white' systems absorb very slightly more light at the blue end
of the spectrum than at the red end. This gives them a very slightly
yellow cast, but we're used to it and don't normally notice until it
gets significant.

Isn't white subjective? Our eyes (and cameras) have auto white balance. Who is to say what real white is?

The optical brighteners absorb in the UV and
fluoresce in the blue, so enhancing the apparent reflectivity at that
end of the spectrum, offsetting the yellow cast and making the paper
or fabric look extra white. But if you use too much, or indeed expose
the stuff to a stronger UV source than normal daylight, then yes it
would and does make them look a bit purple.

Yes, I was thinking of white shellsuits in UV light at a fairground.

Uranium fluoresces in the yellow.

And does something else far more harmful!

in much the same way as they
add them to detergents to make your whites whiter, and fluoresce under
'black light' i.e. UV illumination in night clubs etc)). Besides,
uranium salts are yellow, which isn't what paper mfrs want.


--
A penny saved is ridiculous.