THE 100 MOST INFLUENTIAL INVENTORS OF ALL TIME

7 The 100 Most Influential Inventors of All Time 7

was destroyed by fire in 1839. The partners painted the
scenes on translucent paper or muslin and, by the careful
use of changing lighting effects, were able to present viv-
idly realistic tableaux. The views provided grand,
illusionistic entertainment, and the amazing trompe l’oeil
effect was purposely heightened by the accompaniment
of appropriate music and the positioning of real objects,
animals, or people in front of the painted scenery.
Like many other artists of his time, Daguerre made
preliminary sketches by tracing the images produced by
both the camera obscura and the camera lucida, a prism-
fitted instrument that was invented in 1807. His attempt
to retain the duplication of nature he perceived in the
camera obscura’s ground glass led in 1829 to a partner-
ship with Niépce, with whom he worked in person and
by correspondence for the next four years (Niépce died
in 1833). However, Daguerre’s interest was in shortening
the exposure time necessary to obtain an image of the
real world, while Niépce remained interested in produc-
ing reproducible plates. It appears that by 1835 Daguerre
had discovered that a latent image forms on a plate of
iodized silver and that it can be “developed” and made
visible by exposure to mercury vapour, which settles on
the exposed parts of the image. Exposure times could
thus be reduced from eight hours to 30 minutes. The
results were not permanent, however; when the developed
picture was exposed to light, the unexposed areas of sil-
ver darkened until the image was no longer visible. By
1837 Daguerre was able to fix the image permanently by
using a solution of table salt to dissolve the unexposed
silver iodide. That year he produced a photograph of his
studio on a silvered copper plate, a photograph that was
remarkable for its fidelity and detail. Also that year,
Niépce’s son Isidore signed an agreement with Daguerre