(photographic films and papers) : The process of removal of unexposed and undeveloped halides by converting them to soluble salts. The salts can later be washed from the emulsion. This process makes images stable and unalterable when exposed to light.
Also known as "fixing."
(eye movements) : fixation occurs when eyes stop moving and light from an object's image falls on any point of the retina for a period of time. Central fixation occurs when an object's image falls directly on the eye's fovea.
Please also see: How photojournalism affects the brain.