Фотография /english/

Light is the essential ingredient in photography.Intense exposure causes many particles to form, while weak exposure causes few to form.Photography, then, is based on chemical and physical principles.The sensitivity of silver halides to light is the primary chemical principle.The spectrum comprises the full range of color tones.To the eye, the longest wavelengths register as red, the shortest as blue.Photographic films vary in the way they react to different wavelengths of visible light.Thus, most films now used by amateur and professional photographers are panchromatic.Two additional varieties of black-and-white film-process and chromogenic-have their special uses.Chromogenic film produces dye images rather than silver images on the negative.