Although our digital displays can show literally millions of colours in fact they show us less than half of the possible colours in the world. This is partly because of the reliance on trichromatic devices – what you probably know as RGB. No matter how we choose them, it is impossible to mix together three colours and make all of the other colours. This is despite this embarrassing statement on the BBC website:
Red, yellow and blue are primary colours, which means they can’t be mixed using any other colours. In theory, all other colours can be mixed from these three colours.
This is just plain wrong. It is not the case that in theory, all other colours can be mixed from these three colours. In theory, and in practice, they cannot.
But I digress. The point is that using a three-colour primary system – a trichromatic system – is never going be able to reproduce all of the possible colours in the world. But even if we do use three, we could do better than the current TVs, phones and tablets on the market if we could improve our technology. The problem is that the red, green and blue lights in these displays are not as bright and colourful as they could be. That is where quantum dots come in.
Quantum dots are tiny crystals that can be precisely tuned to efficiently produce very specific colours. The crystals are grown from a mixture of various semiconductor materials and liquid solvents. By carefully controlling the conditions, engineers can adjust the size of the crystals, which determines the wavelength of the light that the crystals emit. Smaller quantum dots, with a diameter of two nanometres (two billionths of a metre) or so, emit short-wavelength, or blue, light. Bigger dots, with diameters closer to eight nanometres, produce light that’s nearer the long-wavelength, or red, end of the spectrum. We can expect to see new technology on the market soon offering brighter and more colourful displays.
I blog about anything related to colour and I am interested in all sorts of aspects of colour whether they be based in arts and design, cultural studies, evolution, chemistry, physics, biology or technology. But a couple of themes keep cropping up and I end up posting about them at regular intervals. So, in 2012 I posted about the historical development of the UK flag – the union jack. And then earlier this year I posted about an article on the BBC about the possible redesign on the union jack is Scotland votes to leave the United Kingdom in the forthcoming referendum there. Some of the designs that were being put forward were really horrible. Perhaps I am too attached to the union jack. A few days ago I came across another BBC story which included 25 readers’ designs for the union jack should Scotland leave. . I must say I much prefer the readers’ designs rather than those previously proposed by experts – the BBC reliably informs me that such experts are known as vexillologists. I like this flag (by David and Gwyneth Parker) – where the blue of Scotland has simply been swapped for the green of Wales, thus preserving the traditional look. (If you wonder why the green of Wales is not in the current flag see my earlier post.)
And I also like the following design (by Matthew Welch), where England and Wales are represented in the top left and bottom right corners respectively and the diagonal stripe represents Northern Ireland of course.
You probably have to be from the UK to understand this humorous design (by Al Main).
You can see all 25 readers’ designs at the BBC here.
If you are interested in vexillology (is that a word?) you may like to read another BBC story about a potential new flag for Norther Ireland. And finally, I was interested that the CIA apparently has a flag database that it makes available to the public.
Could we have developed currency around elements other than gold and silver? Why couldn’t we have coins made out of platinum, for example?
Interesting article today on the BBC website interviewing Professor Sella (University Collage London) about why, of the 118 elements of the periodic table, it is gold (alongside silver) that we value and use for currency.
According to Prof Sella there are reasons to dismiss all the elements apart from gold and silver. For example, you couldn’t use elements that are gas (such as neon) or liquid (mercury) as currency because it would be impractical to carry them around. Several others (such as arsenic and the other liquid, bromine) are poisonous and so could not be practically used. The alkaline metals (those on the left-hand side of the periodic table) are not stable enough (they react with too many other elements). And, of course, say no more about the radioactive elements. Some of the so-called rare earths (such as cerium) could be used but they tend to be even more rare that gold and are actually quite difficult to distinguish from each other.
Prof Sella also postulates reasons for dismissing the 40 transition and post-transition elements such as copper, lead, iron and aluminium. Many are hard to smelt (needing temperatures as high as 1000 deg C) such as titanium and zirconium or hard to extract such as aluminium. Iron is easier to extract and smelt but rusts too easily. Iron is also too abundant.
Prof Sella lists the 8 noble metals (platinum, palladium, rhodium, iridium, osmium and ruthenium, gold and silver) as contenders. However, with the exception of silver and gold they are too rare and have other problems (platinum is hard to extract and has a very high melting point for example). So this leaves gold and silver. The choice of these metals is not arbitrary. It turns out that they have exactly the right properties that we need. They are stable, chemically uninteresting, rare (but not too rare), safe, relatively easy to extract, solid at room temperature and with a reasonably low melting temperature.
The article also explains why gold is golden in colour.
Some of you may recall that last year – a big year for the UK with the Olympics in London and Queen’s jubilee – there was a lot of waving of British flags. I posted about how the flag was derived historically and noted the absence of any representation by Wales. For those who are less familiar, the United Kingdom is a union of four countries (England, Scotland, Wales and Northern Ireland). By contrast Great Britain is just England, Scotland and Wales (not including Northern Ireland) and the British Isles is a geographical feature that includes the United Kingdom and the Republic of Ireland. Simple?
Next year the Scottish people be asked if they want to be independent. If they vote yes (in my opinion this is not very likely, but possible) it will signal the end of the union of Great Britain and Northern Ireland. Today the BBC ran a feature about possible new designs of the new flag. I wasn’t very impressed by any of them, including the horrible one below. Try reading my post first and then the new BBC article.