David Pescovitz writes on Boing Boing: Artist Martin John Callanan and the Advanced Engineered Materials Group at the UK’s National Physical Laboratory used an infinite 3D optical microscope to capture 400 million pixel images of the lowest denomination coin from many currencies. “The Fundamental Units”
How did this collaboration with National Physical Laboratory come about for your project The Fundamental Units?
For six months I was having tests run all around the UK on different types of microscopes such as scanning electron microscopes, at different institutions, universities and testing laboratories. The Curator of Modern Money at the British Museum suggested an idea which eventually lead me to the National Physical Laboratory.
I ended up at the Advanced Engineered Materials Group which is part of the National Physical Laboratory, using an Alicona infinite focus 3D optical microscope.
They were really into experimenting and pushing the equipment. It took about a month of tests to get the results we see. The process involved Petra the scientist in charge of the machine writing programs to capture the data as a whole, as the machine is designed for looking in detail at one tiny part of an object. We crashed it several times working out the right solution. Each coin, which are generally around 18-20mm in diameter, take a whole night to capture. Then computers run for three days assembling the data into extremely high resolution photographic images. We are talking files too big for normal image editing software such as Adobe Photoshop. Each photographic print is from files with around 400 million pixels.
What did some of the earlier tests look like?
Many microscopes are not optical, they don’t use light, and therefore produce results that are removed from what we generally expect to see. A scanning electron microscope, for example (attached), produces images in greyscale and the electric charge greatly emphasises dust and dirt. Clean images could be obtained though sonic cleaning and plating the coins in gold, but this started to become very removed from examining these low value tokens of exchange.
Could you explain the choice to scan these particular coins? How did you get a hold of them?
There are currently 166 active currencies using coins. Using online market places and by contacting national banks I have found the lowest donimation coin for each of these currencies. At the moment, at the beginning, we have imaged one from each continent. All 166 will be imaged.
What are you working on currently?
Well, the UCL European Institute have just (five minuets ago) awarded the research project funding to image the currencies of: Bulgaria, Croatia, Denmark, Hungary, Latvia, Lithuania, Poland, Romania Sweden, and the UK.
Martin John Callanan of the Slade School of Fine Art at University College London contacted the National Physical Laboratory (NPL) as he wanted to put together an exhibition featuring large images of the lowest denomination coins from around the world.
Petra Mildeova from NPL’s Advanced Engineered Materials Group demonstrated that full colour images could be taken using an infinite focus 3D optical microscope. Five coins were imaged (containing over 400 megapixels), allowing coins of less than 20 mm diameter to be printed as 1.2 m diameter images.
Martin John Callanan described the images as “really stunning” and is exhibiting them at the Galleria Horrach Moyà in Mallorca, Spain, in an exhibition entitled ‘The Fundamental Units‘ (referring to the smallest denomination of coins on display and not as a result of working with NPL, the home of fundamental constants in the UK). He now hopes to enhance his exhibition by imaging a further 161 coins, one from each of the other countries around the world that use them.
The images have attracted interest from the British Museum and were featured by New Scientist as their image of the day on 4 December 2012.
The mapping of large areas at very high resolution is becoming a more regular requirement. In fact, the capabilities of the microscope used to produce the images of the coins were barely stretched, as they were only in 2D. Using the Alicona Infinite Focus optical microscope NPL is able to acquire 3D datasets from large areas, which can be used to study worn surfaces on a gear, drill bit or metal punch and hence produce a detailed measurement of the volume of material lost by wear of the component. Such quantified volume measurements can then be used to determine the best material or operating practice for a given material grade.