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Wednesday, December 8, 2004

Arachnid Ice Art

arachnid_art.jpg The cold and ground fog season has arrived at Fourmilab's altitude of 806 metres above mean sea level. One compensation is the surreal beauty of everyday things when decorated by hoarfrost (please, no moronic Slashdot "Score:5, Funny" cracks)--accretion fractal ice crystals grown from moisture in the air. This is a spider web spun in front of the Fourmilab doorbell--you can see how few visitors we get! Ice has encrusted the web, making it glisten in the light. These icy works of natural art are extraordinarily beautiful when the fog clears and the Sun comes out--they reflect light like eldritch strings of diamonds. Today, the weather didn't co-operate, but even under grey skies it was still a pretty sight.

The frost prefers certain kinds of material, which makes for interesting contrasts. As you'd expect for an accretion fractal, sharp points and surfaces with large curvature in one or more dimensions are particularly favoured, just as they are for corona discharges and St. Elmo's fire. A large conifer tree frosted with ice is an exquisite sight.

This isn't one of my better photos. When I discovered the web, it was flexing in the wind and visibly shedding ice, so time was of the essence. The movement meant I had to use a short shutter speed to avoid motion blur, which in turn required a relatively large aperture which reduced depth of field--that's why the bottom right of the web is out of focus (if I shot coplanar with the web, its centre would be lost against the white of the stealth nametag above the doorbell button). This is a handheld shot at f/3.5 and 1/40 second with a Sony DSC-T1 with sensitivity set to ISO 400.

Posted at December 8, 2004 23:00