Lamp:- general term used to describe the various kinds of artificial light sources used in photography.
Lamp black:- pure carbon pigment, made from soot deposited from burning oils.
Lamp house:- light tight housing of an enlarger or projector, which contains the light source.
Lantern slides:- old term used to describe transparencies.
Large format camera:- general term for any camera having a picture format of 4 x 5 inches or larger.
Laser:- abbreviation for Light Amplification by Stimulated Emission of Radiation.
Latensification:- method of increasing relative film speed by fogging after exposure and before development. It can be achieved by chemical or light means.
Latent image:- invisible image produced by exposure which can be made visible by development.
Lateral reversal:- mirror image reversal of the subject from left to right, as found in the viewfinders of some reflex cameras.
Latitude:- degree by which exposure can be varied and still produce an acceptable image. The degree of latitude varies by film type. Faster films tend to have greater latitude than slower films.
LCD:- liquid crystal diode. LCD is an electronic solid state display system commonly used for the face of wrist watches, and also used to display exposure information in the viewfinder of most modern day cameras. A surface can be temporarily changed from transparent to dense black by application of a charge.
The LCD can be programmed to display any required black shape.
Lead acetate:- crystalline, highly poisonous powder used in some toning and intensifying solutions.
Leader:- beginning of a roll of film, which is attached to the camera's take up spool.
Leaf shutter:- see Between the lens shutter.
LED:- light emitting diode. LED is an indicator light used to convey exposure information.
Lens:- optical element made of glass or plastic and capable of bending light. A lens may be constructed of single or multiple elements.
Lens barrel:- metal or plastic tube with a blackened inner surface, in which the lens elements and mechanical components of the lens are mounted.
Lens cap:- plastic, rubber or metal cover which fits over the front or back of the lens to protect it.
Lens coating:- layer or multiple layers of thin anti-reflective materials applied to the surface of lens elements to reduce light reflection and increase the amount of transmitted light.
Lens drive system:- used in autofocus SLR cameras. One type has a motor located inside the lens; in another, a motor inside the camera body turns the lens via a drive shaft.
Lens hood:- opaque tube, either cylindrical, square of funnel shaped, use to shield a lens from stray light outside the field of view.
Lens shade:- see Lens hood.
Lens shutter camera:- camera with the shutter built into the lens.
Lens speed:- largest lens opening (smallest f-number) at which a lens can be set. A fast lens transmits more light and has a larger opening than a slow lens.
Determined by the maximum aperture of the lens in relation to its focal length. The speed of a lens is relative to it's focal length. A 400 mm lens with a maximum aperture of f/3.5 is considered extremely fast, while a 28mm f/3.5 lens is thought to be relatively slow.
Lens system:- describes the type and quantity of lenses available for use with a particular camera.
Lenticular screen:- lens system consisting of a screen containing a number of small lenses.There are two applications of lenticular systems. They are used in some exposure meters to gather light and to determine the angle of acceptance of light by the meter. A lenticular screen consisting of a number of lenses et into rows can be used at the camera stage to produce stereoscopic images by synthesizing binocular vision.
Light:- visible radiated energy which forms part of the electro-magnetic spectrum in the wavelength range of 4000-7000 Å (400-720 nm).
Lightbox:- box of fluorescent tubes balanced for white light and covered with translucent glass or plastic. Used for viewing, registering or correcting film negatives and positives.
Lighting ratio:- ratio of the brightness of light falling on the subject from the main (key) light and other (fill) lights. A ratio of about 3:1 is normal for color photography.
Light meter:- alternate term for exposure meter.
Light sources:- general term applied to any source of light used in photography.
Light tent:- tent like structure made of translucent material hung around a frame. The fabric diffuses the light coming from outside the tent so that highly reflective subjects placed inside the tent can be photographed without reflections.
Light-tight:- term denoting a material or piece of equipment that is impervious to light.
Light trail:- image track recorded on photographic material when a point of light is shifted during exposure.
Light trap:- system of entry to a darkroom which allows easy access, but prevents unwanted light from entering.
Light value:- alternative term for exposure value (EV).
Limiting aperture:- actual size of the aperture formed by the iris diaphragm at any setting.
Linear perspective:- apparent convergence of parallel lines with increasing distance in a two dimensional image.
Line film:- high contrast film which, after correct development, gives negatives of black and white only (with no grays).
Line image:- photographic image consisting of black areas and clear film i.e. white.
Linked Ring Brotherhood:- group of pictorialist photographers who broke away from the Photographic Society of Great Britain. Existed between 1892-1910.
Lippman process:- early color process invented by Professor Gabriel Lippmann (1845-1921). Light first passed through an almost transparent emulsion layer and was then reflected back by a layer of mercury. The interference between reflected and incident light produced a latent image in the emulsion which could be given b&w processing, but when backed with a mirror appeared in color.
Lith film:- extreme form of line film, which produces very high contrast images when used in conjunction with a special lith developer.
Local control:- method of controlling the final quality of a print by increasing or decreasing the exposure given to localized areas of the print by selective masking.
Log e:- logarithmic value (to the base 10) of the relative brightness exposed on the film when undergoing sensitometric testing.
Long focus:- a lens in which the focal length is much greater than the diagonal of the film format with which it is used.
Low key:- photograph in which tones are predominantly dark and there are few highlights.
Lumen:- unit of light intensity falling onto a surface.
Lumen second:- unit to measure the total light output of a photographic source.
Luminance:- measurable amount of light which is emitted by or reflected from a source.
Luminance meter:- alternate term for exposure meter.
Luminescence:- visible light produced from a surface submitted to invisible radiation such as UV, X rays and son on. Unlike fluorescent light it continues to be emitted after the existing source is removed, gradually fading away.
Luminosity:- brightness of either a light source or a reflective surface.
Luminous flux:- intensity of a light source, measured in lumens.