Agfacontour Professional

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Agfa Contour Professional was a sheet film with a special photographic emulsion that after exposure and development in Agfacontour- developers equidensities produced in one pass. Agfacontour was brought onto the market by Agfa in 1970 and was no longer in production in 2002.

Up to the appearance of the Agfacontour film, the following methods were used to produce equidensites:

  • The single-plate process, also called Sabattier or pseudo-solarization process
  • The two-plate process, also known as the negative / positive process
  • The scattered light method
  • Electronic (video) procedures
  • The point measurement with densitometers or densograph
  • Automatic measurement with digitizers

Each of these processes had its drawbacks, with reproducibility in the photographic process and process difficulties in general being arguably the most important drawbacks. Due to difficulties in reproducibility, the quantitative evaluation of the density was only possible with point measurements and a digitizer.

A working group was therefore set up at Agfa to develop a photographic process that fulfilled the following task:

  • Black and white extract of a precisely controllable density range
  • Subdivision into individual density areas, which are designed to be manageable using color conversion or a symbol grid
  • Distance measurement of similar blackenings (especially for blackening gradients)
  • Clarification of information in the case of chaotic density distributions and density gradients

The Agfacontour Professional Sheet Film Emulsion essentially consisted of three components, namely a silver bromide emulsion, a silver chloride emulsion and catalytically active nuclei for physical development, such as B. silver sulfide. Since the two emulsions had different spectral sensitivities, the width of the equidensite could be controlled by means of yellow and magenta filters.

Although the material was quite insensitive (exposure times of minutes were necessary for higher densities), the results were very reproducible and showed second-order equidensites clear and sharp - something that could only be achieved with pseudosolarization with special developers.

The gamma of the Agfacontour film was very high (over 7) and the resolving power was 40 lines / mm.

Graphics

Equidensite number and chromogenic development of the individual black and white extracts

In addition to science, the Agfacontour Professional also opened up many new possibilities for design in advertising graphics and alienation techniques in photography .

literature

  • Kurt Dieter Solf: Equidense film. In: Photography. Fischer Taschenbuch Verlag, Frankfurt am Main 1973, ISBN 3-436-01453-2 , pp. 111-118.
  • H. Mass: Agfacontour Professional in practice. In: Photo technology and economics. No. 2, 1971, p. 39.
  • F. Myšák: The Evaluating of Autoradiographs by Means of the Film Agfacontour Professional . In: Journal Isotopenpraxis Isotopes in Environmental and Health Studies . tape 9 , no. 8 , 1973, p. 280-281 , doi : 10.1080 / 10256017308543671 .

Individual evidence

  1. ↑ Harvey W. Yurow: A Novel Approach to Equidensity Photographic Images. In: Unblinking Eye. Retrieved February 28, 2016 .
  2. ↑ a b c C. Sauer: Agfacontour Professional in Science and Technology. (= Agfa-Gevaert AG publication no. 152). 1st edition. 1974.
  3. ↑ G. Beulig: Fundamentals of Sensitometry . In: Gerhard Teicher (Hrsg.): Handbook of the photo technology . 6th edition. VEB Fotokinoverlag, Leipzig 1974, 3.2.1. Structure, p. 139 .
  4. ↑ US Patent 6083671: Harvey Warren Yurow: Photographic developer for direct production of equidensity images on a high contrast film. filed July 19, 1999, published July 4, 2000.
  5. ↑ Agfacontour Professional in Photography. (= Agfa-Gevaert AG publication no. 151).