The first aristotype paper was marketed in 1867
by the Munich-born chemist Johann Baptist Obernetter.
As the first industrial paper production process
it offered many improvements to the practice
of photography such as ease of use, because it was ready to use, increased sensitivity and better conservation, which quickly attracted amateur photographers. For all those reasons, during the 1880s this process gradually supplanted the use of albumen paper.
Aristotypes are composed by a three-layer process comprising a paper layer, a layer of baryum sulphate
in gelatin and finally a layer of emulsion containing silver chloride suspended in a binder. The use of a baryta layer applied between the paper and the emulsion makes
it possible to achieve purer whites and increases
the brightness of the image. Being hidden
by the baryta layer, the paper fibres are no longer visible.
As it is a Printing-Out Paper process, exposure occurs through contact with the negative in a printing frame, producing a print with identical dimensions
to the negative. Before washing, the print is fixed
and then toned, usually in a gold chloride bath.
Self-toning papers were sold later in the market.
Aristotypes offer very good definition as well as warm tones which vary from red to purplish-brown depending
on the type of toning and the nature of the binder used
in the preparation of the emulsion.
Various binders can be used in the production
of the emulsion for this process. While it is often possible to identify binders by examining visually
the print, in some cases, such as with hybrid processes, the identification of the binder may require further scientific analysis. The two main types of aristotypes take their names from the two most frequently observed binders in collections, namely collodion and gelatin.
The first, the collodion aristotype, was marketed
from 1865 as a result of the work of A. Gaudin
who developed the first positive colloidal silver emulsion, otherwise known as celloidin paper.
It was popular from 1887 until after the First World War when it was gradually superseded by gelatin aristotypes. With reddish-brown to purplish-brown colour variations,
it offered on another hand an excellent image definition and a good chemical stability.
The gelatin aristotype, also known as P.O.P. (Printing Out Paper) gelatin silver chloride emulsion or citrate paper, was introduced in 1882 by the Englishman William de Abney and was mostly used by amateurs. The beginnings
of its industrial production date back to 1884.
In France this technique was developed from 1892
with the marketing of "Aristo" paper by the Lumière brothers. At the same time, P.O.P. and "Solio" paper
were being marketed by the companies Ilford and Kodak respectively. This process was hugely successful until around 1940. These papers were not very sensitive
but offered very good definition. They could be glossy
or matte and ranged from warm brown to black tones.
Aristotypes gradually disappeared from the 1920s onwards following the introduction of developing out processes which reduced exposure time and removed format constraints related to contact printing. However, the companies Kodak and later Guillemot in particular continued to produce aristotype papers until the 1990s.
Visual glossary of photographic techniques
© ARCP / Mairie de Paris, 2015