1263
a considerable reputation amongst political and high
society women in Washington. She is decked out in furs
and an elaborate hat, her head resting on an elegantly
gloved hand as she peers directly into the camera with
an expression combining haughtiness, intelligence, and
perhaps just a hint of vulnerability. Her expression is ac-
centuated by the carved human head on her chair, which
glares at something beyond the picture’s edge. In the
other self-portrait, Johnston is the “Proper Victorian’s”
polar opposite: she sits before a fi replace holding a beer
stein in one hand and a cigarette in the other. Her legs
are casually crossed, prominently displaying petticoats
and an ample sweep of calves. She looks away from the
viewer with a strong, unsmiling mien. The lack of eye
contact reinforces the impression of a tough, no-non-
sense woman making her way in a man’s world. There’s
nothing seductive or feminine about her. This woman is
fully self-contained, breaking the rules without a hint
of apology.
Steichen’s and Benjamin’s self-portraits at the dawn
of the twentieth century may be seen as efforts not just
to refl ect or project themselves through self-portraits
but also to construct multiple selves using the photo-
graphic medium. From the fi rst self-portrait of Bayard
onwards, photographers were often drawn to the plastic
and theatrical possibilities that they discovered in pho-
tography. Photographers during the nineteenth century
increasingly used the medium to examine and portray
the multiplicity of selves that would come to preoccupy
psychologists, sociologists, historians, and countless
artists in the century to come.
David L. Jacobs
SELLA, VITTORIO (1859–1943)
Italian photographer
Vittorio Sella was born on 28th July 1859 in Biella,
where his father, Giuseppe Venanzio, a scientist and
photographer, founded one of the most important Italian
woollen manufactures. In 1856 he published Il Plico del
Fotografo, the fi rst Italian treatise on photography. Vit-
torio’s uncle, Quintino, a government minister, founded
the Club Alpino Italiano in 1863. Vittorio attended a
scientifi c high school and afterwards he worked in the
family fi rm. He learned photography from his father and
thanks to him he also became interested in exploring
and mountaineering. In the course of his life he took
thousands of photographs of the Alps. From 1879 he
worked with scientifi c rigour on many extraordinary
photographic reportages, taken while climbing in the
Italian Alps. He also travelled abroad; in 1889, 1890
and 1896 he was in the Caucasian mountains; in 1897
he took photographs during an ascent of the mountains
of Alaska with the Duke of the Abruzzi. In 1899 he was
in Sikkim in Nepal, and in Africa with the Duke of the
Abruzzi again. He made ascents in the Himalayas (1899,
1909) and took photographs during a trip to Morocco.
His photographs were widely circulated for their quality
and variety and they were found useful by geographers,
topographers and alpinists. Vittorio Sella died in Biella
on 12th August 1943.
Silvia PaoliSENSITOMETRY AND DENSITOMETRY
When Hubert Davy repeated the experiments of Thomas
Wedgwood in 1802, he attempted to convey the rapidity
of his photosensitive preparations and stated, “... the
part concealed by it [the light] remains white, the other
parts speedily become dark.” Some years later, William
Henry Fox Talbot also found the need to indicate the
speed of his materials, and he quantifi ed an experiment
by combining the intensity of the light (“I employed
the full sunshine”) and the time of exposure—“half a
second” (Talbot’s italics).
In the same year (1839), Mungo Ponton drew atten-
tion to a “cheap and simple method” that relied on the
behaviour of light on potassium bichromate to form an
image. He claimed his material was “equally sensitive
with most of the papers prepared with salts of silver” but
admitted, “it is not suffi ciently sensitive for the camera
obscura ...” He had already identifi ed that “the active
power of the light ... resides principally in the violet
rays” by an experiment using light fi ltered to violet,
yellow and red.
Antoine Claudet initiated experiments in 1848 that
he hoped would increase the sensitivity of the da-
guerreotype process to daylight. In order to quantify the
response of his plates, he built a device that he called
the Photographometer, and which provided controllable
conditions of exposure. Like other workers, Claudet
relied on assessing his results by eye.
Unwittingly each of the early practitioners had pro-
vided the basis for the subsequent study of sensitised
materials. Sensitometry became particularly important
when photographers no longer prepared their own
materials but relied on plates manufactured by a third
party. The introduction of dry plates brought a need for
reliable testing in the factories, and a means to audit the
claims for improved speed. Consequently, the role of
sensitometry took on an importance that led to continu-
ing improvements in the practice of photography. For
example, an understanding of the behaviour of sensitised
materials contributed to the design of actinometers
to improve exposures during carbon printing, and to
the accuracy of exposure calculators, which replaced
exposure tables.
As a rule, three requirements were required for a
sensitometric study: