IN THE YEAR 1839, two remarkable processes that would
revolutionize our perceptions of reality were announced
separately in London and Paris; both represented responses
to the challenge of permanently capturing the fleeting
images reflected into the camera obscura. The two systems
involved the application of long-recognized optical and
chemical principles, but aside from this they were only
superficially related. The outcome of one process was a unique, unduplicatable, laterally reversed monochrome picture
on a metal plate that was called a daguerreotype after one of its inventors, Louis Jacques Mande Daguerre (pi.
no. i) (see Profile) . The other system produced an image on
paper that was also monochromatic and tonally as well as
laterally reversed—a negative. When placed in contact with
another chemically treated surface and exposed to sunlight,
the negative image was transferred in reverse, resulting in a
picture with normal spatial and tonal values. The result of
this procedure was called photogenic drawing and evolved
into the calotype, or Talbotype, named after its inventor,
William Henry Fox Talbot (pi. no. 2) (see Profile). For
reasons to be examined later in the chapter, Talbot's negative-positive
process initially was less popular than
Daguerre's unique picture on metal, but it was Talbot's
system that provided the basis for all substantive developments
in photography.
By the time it was announced in 1839, Western industrialized
society was ready for photography. The camera's
images appeared and remained viable because they filled
cultural and sociological needs that were not being met by
pictures created by hand. The photograph was the ultimate
response to a social and cultural appetite for a more accurate
and real-looking representation of reality, a need
that had its origins in the Renaissance. When the idealized
representations of the spiritual universe that inspired the
medieval mind no longer served the purposes of increasingly
secular societies, their places were taken by paintings
and graphic works that portrayed actuality with greater
verisimilitude. To render buildings, topography, and figvires
accurately and in correct proportion, and to suggest
objects and figures in spatial relationships as seen by the
eye rather than the mind, 15th-century painters devised a system of perspective drawyig as well as an optical device
called the camera obscura that projected distant scenes onto
a flat surface (see A Short Technical History, Part I) —both
means remained in use until well into the 19th century.
Realistic depiction in the visual arts was stimulated and
assisted also by the climate of scientific inquiry that had
emerged in the i6th century and was supported by the
middle class during the Enlightenment and the Industrial
Revolution of the late iSth century. Investigations into
plant and animal life on the part of anatomists, botanists,
and physiologists resulted in a body of knowledge concerning
the internal structure as well as superficial appear- ance of living things, improving artists' capacity to portray
organisms credibly. As physical scientists explored aspects
of heat, light, and the solar spectrum, painters became
increasingly aware of the visual effects of weather condi-