X-Nico

3 unusual facts about Callier effect


Callier effect

The directed bright-field (see Fig. 1) has extremely strong directional characteristics by means of a point source and an optical system (condenser); in this case, each point of the photographic film receives light from only one direction.

On the other hand, in a diffused bright-field setup (see Fig. 2) the illumination of the film is provided through a translucent slab (diffuser), and each point of the film receives light from all the directions.

In the absence of scattering, the attenuance provided by the emulsion is independent of the collimation of the illumination; a dense point absorbs a big portion of light and a less dense point absorbs a smaller portion, irrespective of the directional characteristics of the incident light.



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