Eberhard effect

In photographic science, the Eberhard effect, named after Gustav Eberhard, is a special case of two Mackie lines when narrow areas of high and low densities (usually lines approaching within 1 mm.

thickness) cause the two Mackie lines to meet which results in an increased density of this small area.

The effect can be seen quite easily in extreme cases such as in the image of a tree against a grey background of the sky .

The fresh developer at dark places (such as the tree trunk and branches) caused dark streaks in the lighter areas when the developing tray was not moved and the print was taken out in one movement and immediately fixed.

From the print a negative was made which showed a more pleasing result

Negative print wherein the Eberhard Effect became very pronounced due to development without movement