Eberhard effect

The Eberhard effect ( after Gustav Eberhard ( 1867-1940 ) ) or edge effect (also: Saumeffekt ) is a developmental effect in photography, increasing the Kantenschwärzung on the border between strongly and weakly exposed - denotes games - so dark and light.

In case of missing or insufficient movement of the developer is consumed substances Developer concentrate on the dark areas of the image. With rugged light-dark transitions already spent developer diffuses over bright areas where it prevents a full development. Unspent developer gets reversed by bright image parts over adjacent dark spots; there the darkness is therefore gathering pace. In this way, light rims occur at the same time dark and dark fringes around bright objects.

The increase of the contrast at the edges is often visually perceived as improving sharpness appearing. It is composed by the lack of movement of the developing solution, however, often the acute danger that large parts of the subject " verwolken " by non-uniform density.

In color film, there is the inter-image effect; this is related to the Eberhard- or edge effect. Without deterioration of the overall contrast and exposure latitude it causes an increase of the color saturation. This will result in the appropriate processes (eg C -41) by DIR couplers achieved which prevent the formation further silver in the neighborhood strongly exposed areas during development.

A similar sensation gets the edge sharpening in the computer graphics ( which is almost always a pseudo - sharpening, because information that is no longer present, can not be simply re " into magic " ) out. The pixel high-contrast term transitions of the subject are drawn together (or better: together). In contrast to the general sharpening it largely avoids the excessive prominence of the image noise and gfs. of compression artifacts in large parts of the image.

With the Eberhard effect is closely related to the Sabattier effect ( also: pseudo - solarization ). By diffuse Burn the photographic material during development, tonal values ​​are reversed in part, the stay through the lines Eberhard effect caused thereby virtually unchanged and are easily visible.

Swell

  • Http://www.fotografieren.net/glossar/175/eberhard-effekt.html
  • Http://www.techniklexikon.net/d/kanteneffekt/kanteneffekt.htm
  • Http://www.fotolabor.de/fotofachlabor/k.htm # edge effect
  • Photo Lab Technology
  • Photography
C-41 process Solarization (physics)
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