Bell Shape/Profile

[s.ivin at n...]

Photographs of bells (and perhaps curved objects in general) can seem very 
misleading, and it would be a hazardous job to attempt to make measurements
from them.

This may seem a far cry, but in recent months David Hockney has propounded
in a book - 'Secret Knowledge' and with a TV programme that the sharp transition
towards 'photo-realism' made by Dutch artists among others in ca. 1500 was
achieved by optical gadgets of various types (convex mirrors, lenses and
a combination of both) arranged to project an image on to the drawing surface.
Some of his most impressive arguments involve computer manipulation of
pictures - in particular the chandelier from the Arnolfini wedding - where
the captured 2-dimensional image could be rotated in 3-d space to demonstrate
how accurate it looked from any viewing angle.

Do we have any experts out there who could try a similar experiment with a
photo of a bell? Maybe then we could read off some accurate measurements of
diameter at various points, height etc.

Stephen Ivin