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Camera
Obscura
The camera obscura (Lat. dark chamber) was an optical
device used in drawing, and one of the ancestral threads leading
to the invention of photography. Photographic devices today are
still known as "cameras".
The principle of the camera obscura can be demonstrated
with a rudimentry type, just a box (which may be room-size) with
a hole in one wall, (see Pinhole cameras for construction details).
Light from only one part of a scene will pass through the hole and
strike a specific part of the back wall. The projection is made
on paper on which an artist can then copy the image. The advantage
of this technique is that the perspective is right, thus greatly
increasing the realism of the image (correct perspective in drawing
can also be achieved by looking through a wire mesh and copying
the view onto a canvas with a corresponding grid on it). With this
simple do-it-yourself apparatus, the image is always upside-down.
By using mirrors, as in the 18th century overhead version illustrated,
it is also possible to project a right-side-up image. Another more
portable type, as in the second drawing, is a box with an angled
mirror projecting onto tracing paper placed on the glass top, the
image upright as viewed from the back.
As a pinhole is made smaller, the image gets sharper,
but the light-sensitivity decreases. With too small a pinhole the
sharpness again becomes worse due to diffraction. Practical cameras
obscura use a lens rather than a pinhole because it allows a larger
aperture, giving a usable brightness while maintaining focus.
Some cameras obscura have been built as tourist
attractions, though few now survive. Examples can be found in Grahamstown
in South Africa, Bristol in England, Aberystwyth and Portmeirion
in Wales, Kirriemuir, Dumfries and Edinburgh in Scotland, Lisbon
in Portugal, and Santa Monica and San Francisco in California, Havana
in Cuba, Eger in Hungary, and Cádiz in Spain
The principles of the camera obscura have been
known since antiquity. Its potential as a drawing aid may have been
familiar to artists by as early as the 15th century; Leonardo da
Vinci once described the camera obscura.
The Dutch Masters, such as Johannes Vermeer, who
were hired as painters in the 17th Century, were known for their
magnificent attention to detail. It has been widely speculated that
they made use of such a camera, but the extent of their use by artists
at this period remains a matter of considerable controversy.
A freestanding room-sized camera obscura used by the art department
at the University of North Carolina at Chapel Hill. One of the pinholes
can be seen in the panel to the left of the door.
A freestanding room-sized camera obscura in the shape of a camera
located in San Francisco at the Cliff House in Ocean_Beach_(San_Francisco)
Early models were large; comprising either a whole darkened room
or a tent (as employed by Johannes Kepler). By the 18th century,
following developments by Robert Boyle and Robert Hooke, more easily
portable models became available. These were extensively used by
amateur artists while on their travels, but they were also employed
by professionals, including Paul Sandby, Canaletto and Joshua Reynolds,
whose camera (disguised as a book) is now in the Science Museum
(London). Such cameras were later adapted by Louis Daguerre and
William Fox Talbot for creating the first photographs.
The paintings are the excellent portrayal of the events and scenes
that we see around us. The painters are the best cameras of the
world. They reproduce many different types of pictures. They even
draw imaginary pictures that do not exist in this world. We tend
to use both thinned oil paints and dense oil paints. Masterpieces
can be dyed more than once, but each time it may be different from
the existing paintings.h
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