Thursday, 1 September 2011
A few weeks ago I paid my first, long overdue, visit to Dox, the newest - and one of the most successful - of Prague's contemporary art galleries. Here we can see 'Zig Zag Corridor' by op-artist Petr Kvíčala, an unbroken 10cm-wide red line painted directly on the walls of the gallery. The idea is that when viewed end-on, the rectangular lines start to reveal diagonal 'zig-zag' paths, which emerge in a ghostly way from the design. But to me there's a further illusion. Can you see how despite the straightness of all the lines, the walls of the corridor appear to curve or bulge out slightly? Only one person could answer my query, my friend David, a specialist in optical illusions. He told me what was going on:
'It's the Hering illusion, a special case of the more general Zollner illusion. In both, the short cross lines usually extend either side of the long lines that seem to bulge or lean over, but, as here, the effect works even if an edge just abuts an array of short obliques. Amazingly, it was first reported in the edges of the feathers of arrows by Montaigne.' So, now you know!
Click here to view thumbnails for all participants in today's City Daily Photo theme day. Or, for more optical illusions, please visit David's site here. And now I'm feeling just a bit dizzy, so I'm off for a beer to set things straight again.
Topics: Artists and Writers