A technical dictionary of printmaking, André
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- In 1826 Niepce used this term to denote his newly invented process
which later came to be known as photography. The term was replaced in 1839 with the
term daguerréotype, even
though the term photography was already known as of 1836. At the beginning the
latter term had a more general meaning and it was not until 1839 that it became
synonymous with the reproductive process it is now associated with.
- Heliography is also the term used to denote an engraving process in which the
image is obtained by photographic means. The word itself was coined by Niepce, who
made his first "héliography" in 1827; a portrait of the Cardinal of Amboise.
He made several impressions of this first attempt at photographic reproduction.
Niepce's technique consisted in preparing a brass plate with
Syrian asphalt, which has the property of
becoming white and insoluble when exposed to light (the preparation had to be done,
of course, in a dark room). The plate was then exposed or covered with an image
whose black portions did not allow any light to shine through. The exposed areas then
became insoluble whereas the dark areas could be easily dissolved with oil.
All that was then left to do was to etch the plate as in the normal
etching process. Thus heliography, one of
the first photographic processes, was also the first photochemical engraving
In 1853 Niepce's cousin, Niepce de Saint-Victor, presented a paper to the Academy
of Sciences in which he explained, along with Lemaître, their work on
heliogravure. However, what they
called heliogravure was no longer the process mentioned above but rather a
transfer process to be carried out on metal, stone, and, above all, on wood.
The transfer was then followed up by manual or chemical engraving.
Later on heliography became an increasingly specific technique and came to be known
as heliogravure, a general term for
all engraving on wood or metal done on an image that has been transferred by means
of a photographic process.
photographic processes ,
- Heliographic reproduction. A reproductive process using a transparent
support (a tracing drawn with India
ink on a positive film) which is laid against
the emulsion side of heliographic paper. After exposure the paper carries the image.
This kind of chemical reproduction, which is very cheap, was much used to reproduce
technical drawings (projects, diagrams, etc.) as of the middle of the 19th century.
This first papers used for this kind of duplication were the ferro-prussiate papers
which, after being developed and fixed with water, resulted in a white design on a
blue background. The "blue" technical drawing (blue print) has almost entirely
disappeared today. At present other types of paper are used, in particular paper
treated with diazolized salts which, after development, result in brown, black, or
violet lines on a white background.