Those of you who have read other articles on this website will know that very occasionally I go off on a rant that has very little to do with the subject at hand. Previous subjects have been Cheryl Cole, Radio 1, Bearded sandal-wearing Eco-Mentallists, Einstein, and on one occasion wasps and how I'd like a robot that eats them. This time it's Americans. Now don't get me wrong, in general I like Americans, they have an attitude to life that makes it possible for them to do what we never think of in Europe and God alone knows where Europe  and the rest of the world would be now without them helping to stop Uncle Adolf and his gang of Scary Thugs going on the rampage. Thanks for that Yanks, I mean it.


However I would like you to notice the title above.  It contains the word COLOUR in it. Not COLOR. Similarly there is no such thing as Boston Harbor. It's a harbour. And don't get me started about your Labor Day. Labour. LABOUR. L  a  b  o  U   r.

C'mon Hank. What is it about he common U that you don't like?  Your country is not called the Nited States of America, though actually if you don't get that water problem in California I'm hearing about sorted out quite soon a lot of Californians are going to find themselves in a very Nighted State indeed.


The reason for that little rant above was that when I look at charts of colour (COLOUR, NOTICE) like the ones below they're either made in America or they're made by Chinese people who spell things the American way and were I not already completely off my rocker this minor irritation would drive me round the twist.


Now let's have a rant that is connected to the subject at hand. When you used to buy bulbs they had two important pieces of information on them. Those pieces were the wattage and the colour (not color). You could get yellow ones which is what most people preffered at home. You could get white ones (really bright, useful for illuminating things you needed to work on) and blue ones (policemen) and red ones which for some reason were popular in certain parts of Amsterdam..........


Whatever. it would say "yellow" or "blue" or "red" or if the manufacturers were feeling a bit pompous something like "Fireglow Crimson" which meant an orangey-red in plain English. Now it's all Kelvin temperatures. IN GOD'S NAME WHY?????     Kelvin temperatures are important to scientists and engineers but to Mrs Ada Scroggins in the middle of Tesco  looking for a bulb to light her downstairs toilet with it is a device of  Lucifer himself. All a Kelvin temperature does is tell you what colour (not color) the bulb's going to shine so why not just put a word like "yellow" on it like we used to??

I blame the European Union. I have no sound basis for blaming the European Union but I like to blame things on the European Union anyway. If I could, I'd blame the Americans'  inability to spell colour properly on the European Union. In fact I'll blame them facts notwithstanding. EU, it's your fault Hank can't spell colour. Or harbour. Or Labour.


So we are currently about fifty lines in and there's no sign of the subject of this article starting.Sorry about that. It's the European Union's fault and here's a chart for your consideration.

Cribsheet for Colour Temperatures

Go Back lumicrest

This is an extremely good graphic and it's almost self-explanatory. It comes from lumicrest.com who are Canadian and consequently can spell colour properly, and if you click on their chart above it takes you to their website which is full of useful bits. In fact I'm extremely impressed with Lumicrest's web-site and if I lived in Canada I'd definitely be spending a few dollars in their direction.


So let's go through it and examine the sciency  bit

behind it.  What we are looking at here is not the actual temperature of light (it doesn't have one) but a thing called the Correlated Colour Temperature, or CCT. Now here I could bang on for hours about a man called Max Planck and a thing called a black body radiator but I'm not because I guarantee that before I've gone five sentences in you will fall asleep on your keyboard and so suffice it to say that Planck noticed that materials tend to glow when they get hotter and the temperature that they are at determines what colour or shade thereof they glow. Iron is the prime example. Heat it up, it goes red. Heat it some more, it goes orange. Even more and it might melt, but it will go yellow, and so on.


Bulbs give out these shades by heating a filament with electricity and LED lamps do it by chemical reactions with the metals with which they are made. But they all have a colour with which they shine, and that's reflected on the chart there.

So, if Mrs Scroggins in Tesco is looking for a lamp for her downstairs toilet, she might want to consider the yellow part of the chart, about 2700k

Supermarkets themselves use these colours in lightbulbs to present their wares in a good light. For example fish looks better under slightly blue light because blue looks cool and everybody knows the sea is cold and bluish. They paint the fishmonger counter pale blue and use a bulb over 5000k to shine a bluish tint on the fish. Similarly bread looks nicer in yellow so if you use a bulb 3000-3500k then people think it looks nicer and are more tempted to buy it. Jewellers do the same. Gold looks more lustrous in yellow light but silver looks better in white-blue.


So, the easy way to remember is this: 12345  ROY WB  which gives you the approximate CCT in thousands for the colours.


However.........here at Lang Towers we have halogens in the kitchen (don't want the servants working in the dark, it only leads to complaints) and they are 2800k which would make them yellow, according to the chart. Indeed if you look at them they are yellow. However according to the manufacturers they are warm white. This is marketing triumphing over technical. They're yellow, marketing people. Yellow. Warm white sounds like something a drug peddlar might offer you as an alternative to marijuana. Please stop it.

Similarly cool blue is something round 5000k  which at least they've got the colour right this time. In CCT terms it's not cooler, it's hotter. And that's the other confusing thing. The lower down the scale, the warmer the tone is considered and vice-versa. Which explains why they work in marketing. They obviously didn't pass O level physics.

Article and rants tangental and intangental Ian Lang, October 2014




Particularly if you live in Canada.


Harold Wilson (1916 -95)




James Harold Wilson was Prime Minister of Great Britain from 1964 to 1970 and from 1974 to 1976.  Despite his Oxford University background he is seen as a working class hero though in truth he was a dreadful failure as the PM, putting up the top tax rate to 83% thus causing a drain of creative,  technical and scientific brains to friendlier climes and giving huge pay rises to the mineworkers making the collieries economically unviable and dooming the mining industry in Britain. However he does deserve applause for keeping British troops out of the morass that was the Vietnam war. He has a huge statue outside the railway station in his native Huddersfield.


In 1963 he made a speech

warning British industry would be left behind in emerging science and technology and said  a  new Britain would need to be forged in the white heat  of this scientific revolution.


Might have been better not to tax at 83% per cent then, but nonetheless, it shows an understanding of what we are looking at on the right: white heat is 4000k or thereabouts.

(Well, some of the above, but mainly quite a lot of oblique ranting about things.........)