MICRON A unit of length in the metric system equal to 0.001 millimeter.

MILLILITER A unit of volume in the metric system.

1 mL = 0.03381 fl oz

29.57 mL= 1 fl oz

3785 mL= 1 gal

MILLIMETER A unit of length measuring 0.001 of a meter; 25.4 millimeters equal approximately 1 inch.

MILLIMICRON A unit of length in the metric system equal to 0.001 micron. It is also equivalent to 10 angstroms.

MODELING Photographic term for the feeling of plasticity engendered by a photograph or the three-dimensional effect produced in a photograph by effective camera work and lighting. (PIA)

MOTTLE A photographic defect characterized by nonuniform density differences; usually in the pattern of tiny, circular areas.

MOUNT, BAYONET A means of quickly attaching or removing a lens or filter by turning through only part of a revolution.

MOUNTING The process of fastening a photographic print to a support.

NEAR POINT The nearest object to the camera that is still acceptably sharp when the camera is focused for a given distance.

NEGATIVE, BLACK-AND-WHITE A photo-graphic image on film or paper in which light tones are rendered dark and dark tones appear light.

NEGATIVE, COLOR A negative record of the color values of the original object. Not only are light values represented by negative densities but colors are represented negatively by their color complements. (PIA)

NEUTRAL Hueless or achromatic color; gray. Chemically, a solution that is neither acid nor alkaline. (PIA)

NOISE Unwanted sounds or electrical interference in an audio or video signal. In the audio track, there is a hiss or humming sound. In the video picture the interference appears as snow.

NORMAL Sometimes called the perpendicular. An imaginary line forming right angles with a surface or other lines. It is used as a basis for determining angles of incidence, reflection, and refraction.

NOTCHING CODE One or more notches of characteristic shape placed by the manufacturer in one edge of a sheet of photographic film to identify the emulsion side and the emulsion type. (PIA)

NTSC National Television Standards Committee. U.S. standards for television or video signal broadcasting. Also known as the composite signal (Y/C).

OPACITY (l) The ability of an object to absorb light. (2) Photographic term for the light-stopping power of the silver deposit in negative images. Opacity = 100/Transmittance in percent.

OPAQUING All handwork on a negative to remove spots or unwanted images.

OPEN FLASH A method of taking photoflash pictures in which the camera shutter is held open during the flash and then closed.

OPTICAL CENTER The point, generally within a lens but sometimes exterior to it, at which the optical axis and all chief rays of oblique ray bundles intersect.

ORIGINAL Material from which copies are made, such as handwritten copy, typed copy, printed matter, tracings, drawings, and photographs. (IABPAI)

OVERCOATING A thin layer of clear or dyed gelatin sometimes applied on top of the emulsion surface of a film to act as a filter layer or to protect the emulsion from abrasion during exposure and processing.

OVERDEVELOP To permit a photographic image to be developed too much because of one or more of the following factors: (1) excessive time, (2) excessive temperature, (3) overstrength of developer solution, and (4) excessive agitation.

OVEREXPOSE To permit too much exposure of a photographic emulsion. This may be caused by (1) too brilliant light, (2) too large an aperture, or (3) too much time.

OVEREXPOSURE A photographic exposure that exceeds the maximum latitude of the sensitized materials.