Thomas Weber - Photography

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Goya The Parasol
Goya The Parasol
Goya Self-Portrait
Goya Self-Portrait

Zone System (PDF)

Spanish Calotype Photography
(Fotografía Minutera):

My Calotype photography is linked to the Zone System of Ansel Adams. The technical concept of the Calotype was presented in 1839 by W. H. F. Talbot and the Zone System was developed in the 1940s. These two techniques are originally not related to each other. The majority of the today´s photographers producing Calotypes seek to produce prints with the expression of the early times. I take only the basic concept of the Calotype, and the material I use is of the today´s standard quality. If Calotype negatives are enlarged, the prints are of a soft appearance and they never present sharp pictures. But I prefer sharp immages, therefore I only make contact copies. This has a crucial impact on the exposure procedure of the negative. In contrast to the classical procedure contact prints ask for a very accurate exposure. This is the reason why I have introduced the Zone System into my Calotype process.

Basis of the Zone System is the functionality of a photographic light meter. A light meter is technically understood as a volt meter which measures electic tension in a circuit. Every meter has its calibration. A light meter offers the values (f-stop, shutter time) to produce a print of so called „middle grey“, this is a surface of 18% reflection of light. In many cases this works well with objects representing a full scale of different grey values. „The Parasol“ by the famous Spanish painter Francisco Goya shown at the right side reflects such a situation. For situations like this a light meter will offer appropriate values.

The second example is a self-portrait of Goya. The background is black and the face covers only 33% of the whole picture. What is more, the face is of a relatively dull value. A light meter covering the whole scenery would recognize an overall dark surface and will likely offer values which lead to a too bright face in the print. To get correct values it makes sense to measure only the face. European skin reflects between two and four times brighter than „middle grey“, that means 1 or 2 f-stops more. Take only the value of the face selectively and correct that by this factor, then the whole print will show a correct grey tone scale.

With Calotypes using modern paper as film the gradation of the negative is extremely steep. Following the Zone System of Ansel Adams, in terms of f-stops a paper-film is lacking 4 f-stops from black to white compared with a standard (N) gradation film. Such an extremely steep film is not recommended for sceneries lit by bright sunshine. A loss of values in the shadows and highlights is unavoidable – it is the matter of the artist to decide which values will be represented in the print and which will be lost. The artistic fundament of this type of Calotype is its expression by reduction.

Precise knowledge of the capability of the whole photographic procedure, especially that of the negative, is necessary. The Zone System helps to place the grey values of the print precisely and predictably.

© Thomas Weber 2010 - 2021