Why is white not white?

[Brian Gaff (Sofa]

Yes well the same goes for white light too. I always remember the debate when the early home computers came out with 16 colours, but in fact there were only 15, as in the main they had a bright and a normal version of each colour, but how on earth do you get a bright black?

Colour TVs is another case of this, where when it was based on CRTs there were checks made that the whites were to a standard whit. You could buy lights calibrated like that.

In the case of plastic, or paint I've the same when I could see. Some of the whites were almost cream, or in other cases somewhat grey looking.

I don't suppose the various plastic and paint makers get together and decide what white is either. Brian

[alan_m]

The small print in a lot of insurance policies appears to exclude replacing the whole bathroom suite if an exact colour match cannot be found for the broken item.

[Bob Eager]

That was a dark grey.

And the non-bright white was a light grey.

[Max Demian]

That applies to grey(s). And black for that matter.

[williamwright]

Red herring. I didn't think it necessary to exclude mirrors because we are talking about surfaces that scatter light rather than reflect it at a precise angle.

Bill

[williamwright]

A grey that reflected all colours equally could be seen as an inefficient white!

An imperfect black that reflected all colours equally could also be seen as an inefficient white!

A perfect black wouldn't reflect light at all so it doesn't enter into it.

Bi;;

[williamwright]

Black-bright is a colour in Yorkshire. It often describes a child or dog.

Bill

[Max Demian]

Well they're colourless, in the same way that white wine is (mostly) colourless.

Except White Zinfandel is pink. and white coffee is brown. (Relative colours I assume.)

[mechanic]

Yes, white is the most difficult colour to match. Different colour reflection, and different 'sheen' on the tiles make life difficult. Matching tiles seems to call for matching batch numbers from the manufacturer.

[ARW]

[Mark Carver]

Here's an e-mail exchange I had last year with a supplier of a 'White' BT junction box:-

---------------------------------- Hello Dan

Is this item 'snow' White ? Other BT16A boxes I've bought as advertised as 'White' are either grey or cream

Cheers

------------------------------- Hi Mark,

We have the last few "snow" white ones in stock. The manufacturer's have ceased total production so it is quite possible people are sending the cream or grey instead from the stock remaining.

The ones I still have (about 10 remaining in total) are pure bright white.

Regards,

Dan

[PeterC]

The definition of white is that it reflects all parts of the visible (at least) spectrum equally, so your examples are either white or not. No such thing as an imperfect black - it's a coulour of some sort. Under our Sun, a true white would appear to be pink as the sun is slightly towards the red end of the spectrum. There is an inorganic compound that is regarded as white, a salt of manganese ISTR (from nearly 60 years ago) and is pinkish.

[#Paul]

When we had some work done we got the walls painted in the (then) new dulux "light and space" white. We were then surprised that the same builders had thought it a good idea to install *grey* smoke alarms, even though we'd clearly asked for white ones.

Of course, on examination, they *were* white smoke alarms. Just didn't look it (and still don't) not when compared to the much brighter paint.

#Paul

[williamwright]

If it reflects all parts of the spectrum equally, what colour would you say it is?

Under any light source a true white would reflect back all colours in perfect proportion to those emitted by the light source. So yes, but what's your point?

Bill

[PeterC]

As below - it's white, so it is actually all colours. An albino person ist the most coloured example of human skin.

Obvious.

[Martin Brown]

It is remarkably difficult to get white plastics that look white and age gracefully irrespective of the amount of sunshine that they see. Getting a true white is much more difficult than it sounds. How the stuff has been stored (ie in a dark warehouse) can even affect the shade of white!

There are literally zillions of shades of not quite white available!

The closest to a near prefect white is a MgO pigment paint or one of the ludicrously expensive ones with tiny glass spheres in it.

[Steve Walker]

Some years ago my wife dropped a "plate", from under a plant-pot, into the washbasin and put a hole in it. There was already a minor crack in the toilet, from me dropping something years earlier. To our surprise, Direct Line went to great trouble to match the (long out of production) suite and replaced both.

As they were separate events, they were charging two excesses of £50. They were going to send someone to fit them, but I told them that I was happy to fit them myself. They told me that they'd only pay me minimum wage for the time estimated to be needed, but I told them not to bother, I wasn't interested in payment. It worked out well, because they cancelled the £100 of excesses instead.