1140
des Séances de l’Académie des Sciences (vols. 25 and
27, 1848), as well as in his book. In this case copper was
deposited on the lights, fi xed and covered with a solu-
tion of gelatin, which was allowed to set and dry slowly.
Then it was stripped, carrying the copper deposit with
it. In this way he was able to transform daguerreotype
images into negatives from which prints could be made
on silvered papers. Experience from this early work led
him to his most important discovery, the photographic
engraving technique, which happened in 1854.
Poitevin is recognized for establishing the basic
principles of photo-lithography, carbon printing and
collotype printing. In August 1855 he patented a helio-
plastic process, by which fi lms of dichromated gelatin
were exposed to light under a negative and then soaked
in water, which resulted in a relief image from which
a mold could be made. Mungo Ponton in Scotland had
discovered in 1839 the effect of light on dichromates
and William Henry Fox Talbot had in 1853 discovered
that dichromated gelatin which had been exposed to
light would allow greasy ink to adhere to it, although it
repelled water. Based upon these facts Poitevin invented
his new photo-lithographic processes: carbon printing
and collotype printing. A negative was printed onto a
tissue of pigmented gelatin and potassium dichromate
that, when washed and transferred to a second sheet,
produced a durable, rich shiny print. Carbon prints are
noted for their permanence and their rich and glossy
dark tones. The carbon print process reached the height
of its popularity between 1870 and 1910.
His work in heliochromy started in 1865 with some ex-
periments on the possibility of recording colors on paper
coated with silver chloride, similar to the earlier work by
Herschel and Becquerel. First it was necessary to obtain
violet sub-chloride of silver before recording the images.
To sensitize the paper for exposure he dipped the paper
in a solution of potassium dichromate and copper sulfate
and let it dry. When such a paper was exposed to light
beneath a transparent colored picture, such as a painting
on glass, the colors of the picture reproduced on the paper.
The main problem with heliochromy of this type was
how to fi x the images. As a fi xing solution, Poitevin used
water with sulfuric acid and after that glazed the pictures
with albumen, but permanent images proved impossible
to retain. Specimens of the process were exhibited at the
1867 Paris exhibition.
In 1879 he described an iron printing process which
was his last publication in the fi eld of printing processes
based on photographic techniques.
Hans I. Bjelkhagen
Biography
Alphonse Louis Poitevin was born at Confl ans, Sarthe,
France, in 1819, and educated at St. Calais. In 1839
he went to Paris and entered Ecole Centrale des Arts
and Métiers, leaving it in 1843 with a Civil Engineer
Diploma. After the publication of the daguerreotype pro-
cess in 1839, Poitevin took up the study of photography
while still a student at Ecole Centrale. After his Diploma
he was appointed engineer at Eastern Salt Works which
he resigned from in 1855 to move to Paris to work on
his printing process and to start a printing company.
However, he was not that successful in business and he
sold his patent rights to Lemercier, a well-know French
lithographer. At this time Poitevin became a manager
at Pereire’s Chemical Factory in Lyon. From Pereire’s
factory he went to the glassworks at Ahun-les-Mines
and then to those of Falembray. Later he spent some
time in Africa at the mines Kefun Thebul. In 1869 he
returned to France where he started to work at an alum
factory in St. Germain Lambron.
Poitevin was awarded several medals and prizes, e.g., a
silver medal by the Société d’Encouragement des Arts for
his photo-chemical engraving method. For the discovery
of the permanent photographic printing process he was
awarded the Duc de Luyne’s Prize of 20,000 francs and
the Marquis of Argentil’s Prize of 12,000 francs as well as
the order of Chevalier of the Légion d’Honneur. Poitevin
died at Confl ans on March 4, 1882.
See also: Talbot, William Henry Fox Talbot;
Herschel, Sir John Frederick William; and Becquerel,
Edmond Alexandre.Further Reading
Poitevin, A. L., Traité de l’impression photographique sans sels
d’argant, Paris 1862.
Davanne, M. A., Notice sur la vie et les travaux de A. Poitevin,
Paris 1882.
Liesegang, R.E., Die Heliochromie. Das Problem des Pho-
tographirens in natürlichen Farben. Eine Zusammanstellung
der hierauf bezüglichen Arbeiten von Bequerel, Niepce und
Poitevin, , Düsseldorf, Liesegang’s Verlag, 1884.POLAND
Poland of the 19th century was divided up amongst three
neighbouring countries: Russia had the Kingdom of
Poland and Warsaw (i.e., the central area), the Austrian-
Hungarian Empire had Galicia, Lwów and Cracow (i.e.,
the southern and eastern area) and the Prussian Kingdom
had the Poznan part (the western area). After 1945 up
to the present time, the Schlesien, Pommern and Ost-
Preussen territories became part of Poland, however they
were an integral part of Prussia during the 19th century.
As in western Europe, the development of photography
there depended on the demands of a society that was not
as affl uent as that of western Europe. It also depended
on new technological methods being used in France
and Germany. Initially, photographers used to travel to