1061
failed to signifi cantly reduce the level of contaminants
which would, in time, cause fading. The impact of cold
water washing on albumen paper was even greater, with
the cold water reducing the permeability of the albumen
even further.
The practice of using aged fi xers continued until the
mid 1850s, recommended by many writers as a means
of producing a print colour which was consider more
‘pleasing.’ It is remarkable that such a deleterious ef-
fect was directly as a result of a positive decision by
photographers.
It was not until 1855 that the importance of fresh
fi xer and effective washing were widely publicised and
understood. The understanding came, in part at least,
from the scientifi c investigations of Alphonse Davanne
and Jules Girard, published at about the same time as
the ‘Fading Committee’ in London was undertaking its
own exploration.
The most effective solution to the longer term fading
of prints came from the combination of effi cient fi xing
and washing, with gold toning, which greatly reduced
the effect of sulphur on the image structure. The ‘gold
bath’ became an almost universal stage in print pro-
duction, but in spite of it, the effects of sulphur in the
atmosphere over the past century and a half has bleached
the edges of a signifi cant proportion of Victorian prints,
both on salt paper and albumen.
While gold toning may have arrested the lightening
of the developed tones in an albumen print, no counter
was ever discovered for the yellowing of the highlights,
caused by the combined effects of light and pollution
on complex silver/albumen salts which remained within
the paper’s image-carrying layer. While intensifi ers were
produced to ‘redevelop’ faded images, they could not be
used on prints which exhibited this yellowing, as they
effectively developed the highlights as well, introducing
a buff ‘fog’ into the highlights.
Questions over image permanency led, in part, to the
evolution of printing processes which were not exclu-
sively dependent upon the conversion of silver salts to
metallic silver. Carbon, platinum, and pigment processes
all resulted in prints which were impervious to the ef-
fects of air-borne pollution, and which at the same time
expanded the repertoire of the creative printer.
Other permanent printing processes grew out of the
quest for methods which would facilitate print produc-
tion on a truly commercial scale—such as Woodbury-
type, Autotype, and others—and the introduction of
ink-based lithographic and gravure processes.
John Hannavy
See also: Salted Paper Print; Albumen Print;
Printing and Contact Printing and Printing Frames;
Carbon Print; Platinum Print; and Woodburytype,
Woodburygravure.
Further reading
Hunt, Robert, A Manual of Photography, London: Richard Griffi n
and Company, 1857.
Tissandier, Gaston (trans, John Thomson), History and Handbook
of Photography, London: Sampson, Low, Marston, Searle &
Rivington, 1878, reprinted New York: Arno Press, 1973.
Sparling, W., The Theory and Practice of the Photographic Art,
London: Houlston and Stoneman; Wm S. Orr and Co, 1856.
Wall, E.J., Dictionary of Photography, London: Hazel, Watson
& Viney, 1897.
Crawford, William. The Keepers of Light, New York: Morgan
& Morgan, 1979.
Hardwich, T. Frederick. A Manual of Photographic Chemistry,
London: John Churchill, 1855.
Wilde, F., “The Permanency of Photographs—Silver, Carbon,
and Platinum.” American Journal of Photography , vol. 12,
no. 134, Feb. 1891.
Blanquart-Évrard, Louis-Désiré, Traité de photographie sur
papier. Paris: Librairie encyclopédique Roret, 1851.
Reilly, James M., The Albumen and Salted Paper Book: The
History and Practice of Photographic Printing, 1840–1895,
Rochester, New York: Light Impressions, 1980.PERSPECTIVE
In photography, as in art, there are generally accepted to
be two forms of perspective worthy of consideration–lin-
ear perspective and aerial perspective. The importance
of both was clearly and distinctly understood from the
earliest days of the medium.
Linear perspective—sometimes referred to as iso-
metrical perspective by nineteenth century practitio-
ners—is the phenomenon by which the spatial aspects
of the three dimensional world in which we live are rec-
ognized by issues of apparent visible scale. The distance
that we perceive in three dimensions is conveyed and
visibly recreated in two dimensions by our recognition
and understanding of those changes in scale. Thus, an
object that appears smaller in a photographic print or
a painting is read as being further away from the eye
or the camera lens from a similarly sized object that is
reproduced larger.
Aerial perspective—the term was coined by Leon-
ardo da Vinci—has, on the other hand, long been un-
derstood as the enhancement, or otherwise, of the sense
of distance conveyed in a picture by the effect of haze,
smoke or water vapor in the air.
While the former implies distance by the convergence
of lines towards a notional vanishing point, the latter
uses the reduced distinctiveness of objects farther from
the lens to imply their distance from the viewer.
The conditions which produced marked aerial per-
spective were not always seen as being advantageous
to the photographer. Especially in the 1850s, when the
pursuit of technical excellence was seen to be of greater
importance than effect, aerial pollution was seen as a
distinct problem, especially in cities where the smoke