1080
Kathleen Stewart Howe, 67–75, Albuquerque: University of
New Mexico Press, 1998.
Weber, Bruno, “Mit Photochrom in fünf Kontinenten,” Turicum
10 (1979): 33–41 [“With the Photochrom on Five Continents”]
The PhotoHistorian, 133 (2001), supplement: 1–8.
——, “Rund um die Welt in Photochrom [Round the World in
Photochrom].” In Deutschland um die Jahrhundertwende,
145–150, Zürich: Orell Füssli, 1990.
PHOTOGLYPHIC ENGRAVING
Photoglyphic Engraving is an early process of pho-
togravure invented by William Henry Fox Talbot
(1800–1877), but one that was rapidly superseded by
the Talbot-Klic process of 1879. Talbot’s fi rst pho-
tomechanical invention, “Improvements in the art of
engraving, in which photographic processes are used”
(English. Pat. No. 565), was recorded in 1852. Talbot
had discovered the light-sensitivity of a mixture of
potassium dichromate and gelatin. He was the fi rst
researcher to publish the fact that chromated gelatin
becomes insoluble after exposure to light and loses its
capacity of swelling in cold water.
He applied this principle to a printing process that
made use of dichromated gelatin coated on a steel plate
prepared for engraving. When dry, the gelatin coating
was exposed to sunlight under a positive image. After
exposure, the parts of the gelatin coating that were not
exposed to light were dissolved in hot water, leaving a
relief image. The plate was then ready for etching with
bichloride of platinum, which was poured over the plate.
This solution would fi rst attack the thinner parts of the
gelatin relief and would leave a depression in areas that
were protected from light by the positive image. This
depression could be fi lled with ink like any intaglio plate
(etchings, line engravings, etc.) and the resulting image
could be transferred onto paper with a printing press.
One can easily imagine that Talbot’s fi rst results were
suitable for line reproductions. For the production of
prints that produced the shades of a real photograph
he invented a primitive form of half-tone screen: pho-
tographic veils. To quote from the patent abridgement,
“To produce the effect of engraved lines or of uniform
shading, the image of a piece of folded gauze, or other
suitable material, is impressed upon the gelatin prior to
the image of the object required being formed. Plates of
zinc or lithographic stones are also readily engraved by
this process.” Nevertheless, Talbot himself admitted that
his fi rst photomechanical invention did not succeed in
reproducing photographs with a full range of tones.
In his follow-up patent of 1858 (No. 875), he intro-
duces new modes of etching. With the fi rst method the
picture is no longer washed, but as soon as it is removed
from the copying frame it is covered with pulverized
copal or other resin. This fi ne powder is then heated
over a lamp, which makes it melt and stick to the plate.
When the plate has cooled it is etched by means of a
nearly saturated solution of perchloride of iron in water;
the etching being accomplished in consequence of the
perchloride solution penetrating the gelatin wherever the
light has acted upon it, but refusing to penetrate those
parts upon which the light has suffi ciently acted.
Once again, we see an idea borrowed from tradi-
tional printmaking. In this case, it is the old aquatint
etching process invented in the 1760s by J.B. Le Prince
(1734–1784). With this intaglio process a full scale of
tone is obtained by etching a multitude of extremely
small pockmarks in a random manner on the printing
plate. Niepce de Saint-Victor had documented the use
of the aquatint grain in his Traité Pratique de Gravure
Héliographique (Paris, 1856, 44).
In another variant of the etching process, the exposed
picture is washed in warm water before receiving the
resin powder. Another method made use of an elec-
trotype etching. Specimens of Talbot’s new processes
appeared in Photographic News in 1858 as reproduc-
tions of photographs of Spain, France and elsewhere by
Soulier and Clouzard. William Crookes, the publisher
of Photographic News, was quite impressed by Talbot’s
new invention:
We have recently been favoured with the inspection of
some new photographic prints, or to speak more cor-
rectly, PHOTOGLYPHIC ENGRAVINGS, executed by a
new process, the result of experiments made by Mr. H.
Fox Talbot. By means of his invention common paper
photographs can be transferred to plates of steel, copper,
or zinc, and impressions printed off afterwards with the
usual printer’s ink. The plates engraved by this mode are
indeed beautiful in themselves as photographs, and will
bear strong microscopic inspection, the most minute
detail being given with astonishing fi delity. They are free
from many of the imperfections which were so evident in
former attempts, and the manner in which the half-tones
are given is really wonderful; the specimens are of various
subjects, showing the perfection which can be obtained in
any branch of pictures. Even in these copies the detail is so
fi ne that when a powerful microscopic power is brought
to bear on them, we are enabled to trace the names in
the shops in the distance, and easily read the play-bills
in the foreground, and this in a picture only a few inches
square, while the minuteness in architectural subjects is
most remarkable. In a view of Paris there is all that can
be desired in half-tones, and the perspective is almost as
good as in a photograph.
The new invention was named “Photoglyphic En-
graving” by Talbot and led to a considerable amount
of activity among experimenters. It eventually evolved
in what became known as the Talbot-Klic process,
which was introduced in 1879, two years after Talbot’s
death.
This process is also referred to as heliographic
etching with chromated gelatin process, photographic