Colour-change Paperweight

Alexandrite is an extremely rare gemstone with the property to change from purple to green. It appears purple under artificial light and green when viewed in daylight. The gemstone is named for Tsar Alexander II of Russia, on whose 16th birthday it was discovered, and fine examples can cost up to $100,000 per carat. I was quite astonished to discover that a rather less expensive Caithness glass paperweight in my possession for the last twenty years can do more or less the same thing! In daylight, or under normal incandescent or halogen lighting it appears a rich purple:

But I recently installed compact flourescent lighting, and under this the paperweight turns blue:

The likely explanation for this phenomenon is that the purple-coloured glass contains a mixture of red and blue colourants. Under daylight or a continuous-spectrum artificial light, these appear purple. However flourescent lighting is deficiant in red wavelengths and when illuminated by such lighting, the red colourants are not seen, causing the paperweight to appear blue.

© Christopher Seddon 2008

Tempelhof Airport, Berlin

Opened in 1923, Tempelhof is one of the world’s oldest airports still in operation and one of three airports in Berlin. It was completely reconstructed by the Nazis between 1936 and 1941 and at the time was one of the largest manmade structures on Earth. After the war the airport played a major role in the Berlin Airlift and the USAF operated from it throughout the Cold War, but its use declined thereafter. Sadly this historic airport’s days are numbered and it is scheduled to close at the end of this month, the plan being that nearby Schonefeldt will be expanded and will eventually bcome Berlin’s sole airport.

© Christopher Seddon 2008

Berliner Fernsehturm

Located near Alexanderplatz in what was then East Berlin and constructed between 1965 and 1969, the Berliner Fernsehturm (TV Tower) is easily visible across the whole of Berlin, as its instigator, Walter Ulbricht presumably intended. Ironically, the design was based on a similar structure in Stuttgart, in the capitalist west!

The tower is featured in English artist Tacita Dean’s 2001 work entitled ‘Fernsehturm’ and in 2006 the sphere was decorated as a football to mark Germany’s hosting of the World Cup, a tournament that the Germans uncharacteristically failed to win.

The tower is shown framed between two stairwells of the now-demolished Palast der Republik, another icon of the former Communist regime.

© Christopher Seddon 2008