September 2007

Persistence of Persistence of Vision


You know why movies seem to be continuous motion even though they’re really just static images being shown at 48 frames per second — persistence of vision, right? Well, there’s a great article on the Grand Illusions site about how that explanation is ‘simple to understand’, ‘elegant’, even ‘poetic’… and also fundamentally incorrect.

Apparently psychologists have known for almost as long as film has been around that the explanation was bunk, but somehow film historians find it too compelling an explanation to give it up. Somehow, the image that images persist… persists.

Tips on buying a diamond


A diamond broker I talked to recently mentioned an interesting heuristic: he never buys diamonds that are exactly 1 carat, because he figures the person cutting the diamond almost certainly sacrificed some quality in order to bring it up to that magic number. and he never guys diamonds that are .98 or .99 carats either, because he figures the cutter was trying to sacrifice quality for the magic number, and then screwed up besides.