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By Jed Freudenthal - 09:21 AM, 04-24-2006 Edit Rating: None
HIGH DEFINTION DEVELOPERS AT THE APUG MEETING IN RAVENSTEIN ( THE NETHERLANDS), APRIL 23 2006.At the meeting were APUG members from Germany and the Netherlands.High definition developers have the ability to transfer contrast accurately on a microscale, influencing the image quality of a photographic image. The transfer of contrast can be described in a mathematical way (MTF). However, many people are unable to relate mathematical formulas to the beauty or quality of a photographic image. Not that strange, because the MTF description handles the objective transfer of an image, the way a physicist is looking at it. In the judgement of the quality of a photographic image, a personnel perception ( psychology of a person) is involved.For that reason, the effect of high definition film developers were judged at the APUG meeting on the basis of looking at actual 16x20? prints and negatives, instead of using the Modulation Transfer Functions (MTF) or the effect of the high spatial frequencies on the quality of an image. The effect on image quality of the pyrocatechein and pyrogallol developers, as descibed in HIGH DEFINITION DEVELOPER, STAINING AND NON-STAINING ( Film Developers / STAINING) was judged at the meeting on the basis of looking at actual 16x20" prints and negatives. An explanation of this judgement is then given in terms of the accurate transfer of contrast on a microscale ( reproduction of fine details) and the HD curves measured by Harry Kamp.The pyrocatechein developer has also been applied for different photographic lenses for 4x5" as well as 6x6 cm negatives. The lenses were a Rodenstock Sironar-S 150/5,6 , a Schneider Super Angulon 90/8 for 4x5" and a Zeiss Distagon 40/4 for 6x6 cm. In this way the differences and qualities of these lenses could be investigated and discussed on the basis of actual prints.In the near future, a workshop will be organized where the participants will make photographs with their own equipment ( different lenses) of the same subject. Then, the negatives will be developed in the high definition developers and prints will be made (in a large darkroom). The, the results will be discussed. And, hopefully, the participants can select their photographic materials in a more optimal way.
Jed