diffusion

Definition: (1) Of light: scattering beam of light in many directions caused by sending light through semi-translucent screen e.g. nylon sheet or cloud or through smoke; reflecting light from matte surface eg ground glass or paper. Effect is to 'soften' light and results in lowering of contrast and blurring of edge of shadows. (2) Of chemicals: movement of molecules in gas or liquid medium from region of low concentration to one of high concentration.

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