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.
An article in Stuff reveals what 3D Systems claims to be the world’s first continuous-tone full colour 3D plastic printer, called the ProJet 4500.The ProJet 4500 offers full-colour parts with colours that are able to blend into each other with gradient transitions.
I didn’t realise how sophisticated reindeers are. It turns out they have two layers of fur to help them keep warm, are able to shrink the pads on their hooves to give then better grip, and can detect ultraviolet light which enables them too see in very dim light. And it also turns out that their eyes can change colour in winter so that their vision is more sensitive. Reindeers, like cats, have a reflective layer behind the retina (which is the inside of the eye ball where all the light-sensitive cells are) that helps them to see in dim light. This is why, if you see a cat at night, you might see the eyes shining; you are seeing light being reflected back at you from the cat’s tapetum lucidum (which is the technical term for the layer behind the retina). The light that shines back in most animals with this layer is golden but in reindeer it apparently shifts to blue in the winter. The shift to blue allows more light to be scattered and improves the vision of the animal.
The full paper can be read in the Proceedings of the Royal Society.
I would argue that there is no such thing as visible light – or at least that the term visible light is a meaningless one.
Light is part of the electromagnetic spectrum which is describes electromagnetic radiation by its wavelength. An electromagnetic wave has both electric and magnetic field components. What is really very interesting is that depending upon the wavelength of the field the electromagnetic radiation has very different properties and we give it a different name.
When the wavelength is very long, the radiation is radio waves or micro waves. When the wavelength is very short, the radiation is x-rays or gamma rays. There is a narrow range of wavelengths (from about 360 nm to about 780 nm – a nm is 0.000000001 of a metre) to which our eyes are sensitive. Because we can literally see this radiation we call it light. I still find it amazing that light, x-rays, radio waves, and microwaves are all essentially the same thing (electromagnetic radiation) with just a change in the wavelength!! However, my point for today is that light is radiation that is visible – to talk about visible light would be bizarre since by its very definition light is visible. Technically, visible light is a pleonasm; pleonasm is a word derived from the Greek word “pleon” meaning excessive. Other examples of pleonasms – easily confused with oxymora – include the phrases end result and invited guests.
Very interested in this new colour-measurement device called the swatchmate cube.
The new device is launched by Swatchmate on November 13th. That;s two day’s time from now. It captures the colour and displays it on your smartphone. Does it provide any numerical data such as CIELAB? I don’t know. How much is it? I don’t know. I guess we’ll find out at the launch!!
A few years ago I just didn’t really get the Kindle. Why would anyone buy a device that looks and behaves like something several generations behind a modern tablet? After all, can’t an iPad do every a Kindle can do and lots more? That was before I tried a Kindle and understood what people mean by e-paper. Fundamentally an iPad is a light-emissive device whereas the Kindle is a light-reflective device. In the dark the iPad is great but try reading it on a sun bed on holiday. Whereas the Kindle is hard to read in the dark but is easier to read in very bright conditions; just like an old-fashioned book or newspaper.
But there are two things that still let e-paper technology down. The refresh rate is slow and it’s mainly still just shades of grey. Where is the colour e-paper that promised to revolutionise our mobile displays? According to industry expert Sean Buckley the technology of colour e-paper may be grinding to a halt. And now it seems that consumers are losing interest in e-readers anyway. To read Sean’s fascinating account in full please click here.
I have worked in colour for pretty much all my working life. Though it has led to a rewarding and stimulating career (with a little bit of success) and though my passion for colour has never waned, I do sometimes wonder if i could have put my life to something more useful. Not that colour is not useful, far from it, but what I mean is something that could save lives. For example, perhaps I could have become a researcher looking into a cure for cancer. Compared with research like that, doesn’t colour sometimes seem frivolous and secondary?
So my Friday morning today was just cheered up a little when I came across an article in the Grundig about how colour-changing technology could revolutionise the medical industry. Apparently, 1.3 million people die each year because of unsafe injections, making the humble injection the most dangerous clinical procedure in the world. Part of the problem is that syringes are sometimes accidentally reused without sterilisation.
In response to this serious issue, David Swann at the University of Huddersfield – just down the road from where I work – developed a “behaviour-changing syringe” that warns when the needle is unsafe. Once opened the syringe turns bright red within sixty seconds. It’s not even expense. Apparently a standard syringe costs 2.5 pence whereas the “behaviour-changing syringe” costs 2.65 pence.
See the original article here.
Of course, one of the reasons (but by far not the only one) that the iphone has been so successful is the quality of the camera that is built in. It was certainly one of the features that made me switch from Nokia about 3 years ago after more than 15 years of loyalty to the swedish brand. So I was interested to read recently that the next iphone may feature advanced colour correction methods and promises to be even better than its predecessors. You can read about the story here.
Colour correction is necessary because different cameras use different RGB primaries and because the activation of the RGB sensors when taking an image depend upon the quantity and quality of the ambient illumination. So, for example, imagine the light was very very red, then the R channel of the camera would be more strongly activated than if the light was whiter. However, our visual systems are able to compensate for this so that most of the time we don’t notice objects changing colour when we move from one room to another or from inside to outside. Colour correction is inspired by human colour constancy and attempt to correct the images so that the objects in the scene would retain their daylight appearance. However, colour correction is difficult; that is, it is very difficult to get it right all of the time. One frustration I have is taking a photo of my band (I play drums in a covers band) under very colourful lighting. Often the images are very disappointing and lack the intensity of the original scene. That is because, human colour constancy is only partial and under extreme lighting things really do change colour markedly – such as under our intense LED stage lighting. In these cases I think sometimes the automatic colour correction is actually too much and I have found that I have to modify the images I capture on my mac to try to recreate what I think the original scene looked like. So auto colour correction – the state of the art – is certainly not perfect. Let’s hope this story about an advance made by Apple is true.
Another simulator on the market that shows you what your image or website would look like to someone who is colour blind. This one is from a company called ETRE – for further details see http://www.etre.com/tools/colourblindsimulator/
In the image series below the left image is normal and the ones in the middle and right show protonopia and deuteranopia respectively.
For more on colour blindness see my earlier post.
A while ago I posted about whether colour blindness was something that designers should take more seriously. After all, about 8% of all the men in the world are colour blind. Of course, this does not mean that they cannot see colour (the term, colour blindness is a bit of a misnomer) but it does mean that they have difficulty discriminating between colours that the rest of us can easily tell apart. In my original post I was referring to the computer game, Call of Duty, and whether the gameplay could be reduced for colour blind players who may have difficulty telling the various colour tags apart that appear on the screen.
So it was quite interesting that I just came across news that the developers of SimCity have added three special colour filters that make adjustments to the colours on screen so that colour blind players can better discriminate. A great idea – but about time!!