413
Chemical development may be said to have begun
around 1860, with the anonymous American practice of
fuming an exposed, dry-collodion plate with ammonia,
prior to developing it with a neutral solution containing
pyrogallic acid. More certifi ably, it may be said to have
begun in 1862–1863, with the publication of Major
Russell’s bromided pyro-ammonia formula. By the end
of the nineteenth century, it was the prevailing method
of developing.
At fi rst, chemical development was exclusively used
to make negatives, but by the 1880s, it also had come
into regular use for developing positive prints. During
this period, chemical development was used in the fol-
lowing photographic processes: the dry-collodion pro-
cess (beginning ca. 1860), the gelatin dry-plate process
(beginning 1871), and the various bromide, chloride, and
chlorobromide positive printing processes (beginning
ca. 1874). Signifi cant reagents used during this period
were pyrogallic acid (beginning ca. 1860), hydroquinone
and pyrocatechin (beginning 1880), amidol, glycin,
metol, and para-aminophenol (beginning 1891).
In order to form a photographic image by chemical
development, the excess silver nitrate used in forming
the light-sensitive silver halide needed to be removed.
At fi rst, this was achieved by rinsing the sensitized
sheet of glass or paper in water; but following the in-
troduction of gelatin dry-plates in 1871–1873, the silver
bromide emulsion was rinsed prior to being coated on
the glass. Following the rinsing stage, only the silver
halide remained, so a reagent could then be employed
in an alkaline solution in which the alkali acted as an
accelerator, reducing both exposure and development
times by absorbing the released halogen at the same
time as the reagent reduced silver.
In spite of the great improvement made in removing
the excess silver prior to development in an alkaline
solution, chemical development still had an undesirable
tendency to reduce all of the silver halide in the nega-
tive to silver, rather than just the exposed areas. This
problem—known as chemical fog—was only partially
held in check by the use of a restrainer (i.e., ammonium
bromide) in the earliest pyro-ammonia developing
solutions, because the reagent exhausted rapidly in the
absence of an oxygen-absorbing preservative. In this
regard, the introduction of sodium sulfi te in 1882 marked
a signifi cant advance. Similarly, the silver bromide
grains suspended across the gelatin dry-plate emulsions
required more selective developing agents, resulting in
the introduction of numerous patented reagents from
1880 onwards. With the introduction of the fi rst metol-
hydroquinone combination in 1893, the stage was set
for most of the black-and-white developing formulations
that would predominate in the twentieth century.
Alan GreeneSee also: Calotype and Talbotype; Dry Plate
Negatives: Gelatine; Fixing; Waxed Paper Negative
Processes; and Wet Collodion Negative.Further Reading
Davanne, Alphonse, La Photographie: traité théorique et pratique
[Photography: A Theoretical and Practical Treatise], 2 vols.,
Paris: Gauthier-Villars, 1888.
Eder, Josef Maria, History of Photography, trans. Edward Eps-
tean, 1945, reprint, New York: Dover, 1978.
Hardwich, T. Frederick, A Manual of Photographic Chemistry,
4th ed., London: John Churchill, 1857.
James, Thomas Howard and George C. Higgins, Fundamentals
of Photographic Theory, rev. ed., New York: Morgan and
Morgan, 1960.
Jones, Bernard E. ed., Encyclopedia of Photography, 1911,
reprint. New York: Arno, 1974
Mason, Leslie Frederick Alfred, Photographic Processing Chem-
istry, 2nd ed. New York, John Wiley, 1975.
Neblette, Carroll Bernard, Photography: Its Materials and Pro-
cesses, 5th ed. Princeton, N.J.: Van Nostrand, 1952.
Seyewetz, Alphonse, Le développement de l’image latente en
photographie [The Development of the Latent Image in
Photography], Paris: Gauthier-Villars, 1899.
Wall, Edward John and Franklin I. Jordan, Photographic Facts
and Formulas, Boston: American Photographic Publishing
Co., 1940.DEVERIA, ACHILLES (1800–1857) AND
THÉODULE (1831–1871)
Father and son Achilles and Théodule Devéria practiced
photography on paper from the early 1850s. Achilles
Jacques Jean Marie Devéria, born on February 6, 1800
in Paris, also raised painters Laffi te and Girodet, and
was primarily known for his work as a draughtsman,
engraver, and especially lithographer. In this technique,
which he intensively practiced beginning in the 1830s,
he left an enormous and eclectic body of work, in
particular, reproductions of pictures of his brother, the
painter Eugene Devéria (1808–1865).
When he entered the Estampes de la Bibliothèque
Nationale in 1848, he was interested in photography
on paper like many painters and engravers of his gen-
eration. Among his friendships of the period was one
with Louis Robert, a photo hobbyist and director of the
painting workshops of the Porcelain factory of Sevres- for whom Devéria worked episodically from 1839 to
- Nevertheless, it remains diffi cult to determine with
certainty the degree of involvement Devéria had in the
new medium. It appears in 1853 in Paris at the begin-
ning of the publication of the fi rst French scientifi c work
illustrated by photography, Photographie zoologique ou
représentation des animaux rares des collections du mu-
sée d’histoire naturelle, which contained photogravures
by Abel Niépce de Saint Victor based on photographs
made by Louis Rousseau, assistant at the Museum and,