medieval photography
Allan Janus (NASARC07@SIVM.SI.EDU)
Wed, 18 Oct 95 22:51:03 EDT
Well, there was the Cathedrale di camera obscura - Leonardo got hold of
a disused cathedral and blackened all the stained glass, except for the
very center of the rose window, which he replaced with a bullseye lens.
He then covered the alterpiece with plaster. While it was still wet, he
coated the entire expanse with a solution of lunar caustic. An ingenious
mechanism removed the lens cap from the front of the cathedral, and the
exposure of the town square began. Leonardo immediately ran into
difficulties - the fresco needed to be kept damp with constant
applications of fresh plaster, which covered up the lunar caustic before
the exposure - which Leonardo calculated to be 6 months - had
progressed. Leonardo hired an out-of-work band of German landknechts to
keep applying the plaster and lunar caustic, but when he fell behind in
their pay, they looted and pillaged the town. This tragic occurrence,
coupled with the impossibility of fixing any image and the difficulty of
making a 65 foot contact print on the wall of a cathedral (hard to get
the paper - nothing changes) set back the progress of photography for
another 300 years. Finally, although Leonardo would never admit it,
there was absolutely no interest in huge photographs of Italian city
squares - so the wet-piazza process remains relatively unknown to this
day.
Allan Janus
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