PHOTOGRAPHY GLOSSARY (H-L)
Glossary - H
Halation - diffused ring of light
typically formed around small brilliant highlight areas in the
subject. It is caused by light passing straight through the emulsion
and being reflected back by the film base on the light sensitive
layer. This records slightly out of register with the original
Halogens -a group of chemical elements. In photography,
three of these, bromine, chlorine and iodine are used with silver
to produce light sensitive material.
Half-frame - negative format of 18 x 24mm. Images
are recorded on a vertical axis on standard 35mm film, thus giving
72 half-frame images on film designed for 36 exposures.
Half-frame camera - camera designed to use 35mm
film in a half-frame format.
Half-plate - picture format measuring 4 ¾
x 6 ½ inches. Some early cameras produced negatives of
Half-silvered mirror is a glass sheet evenly coated
with a substance which transmits part of the light incident on it and reflects the remainder.
Used for beam splitting devices in holography, and for front projection.
Halftone - mechanical process for printing continuous
tone images in ink.
Halogens - collective term for the elements chlorine,
bromine and iodine, which are combined with silver to produce
the light sensitive crystals used as the basis for photographic
Hand coloring - process of applying color tints,
in the form of paint, to a photographic image to create or enhance
the color effect.
Hanger - frame for holding sheet film for processing.
Hard - defines a scene, negative or print with high
Hardeners - chemicals often used with a fixing bath to strengthen the physical
characteristics of an emulsion. The most common hardeners are
potassium or chrome alum.
Hard gradation - term denoting the quality of harsh
contrast in a photograph.
Heat filter - optical attachment made of thick infrared
absorbing glass, used to absorb heat radiation from alight source
without diminishing output.
Heliography - early photographic process invented
by Niepce, employing a polished pewter plate coated with bitumen
Herschel effect - the destruction of an exposed
image by infrared radiation.
Hide - camouflaged barrier used by natural history
and wildlife photographers.
High art photography - general term for an early
form of artistic photography (1851-1870), in which photographers
set out to match the style and subject matter of paintings of
High contrast developer - solutions used to produce
high contrast images.
High key - photograph which contains large areas
of light tones, with few middle tomes or shadows.
Highlights - the brightest ares of the subject,
represented on a negative by dense deposits of black metallic
silver, but reproducing as bright areas on the positive print.
Hill cloud lens - lens with a 180° angle of
view, used for photographing cloud formations and other meteorological
Holding back - 1. Shortening the development time
given to film to help reduce image contrast. 2. Method of decreasing
exposure given to selective areas of the print. Also referred
to as dodging.
Holography - system of photography,
using neither a camera not lens, in which laser beams create an
interference patter recorded directly on appropriate light sensitive
sheet film or plates. After processing, viewing the image by the
light of a laser gives a three dimensional image.
Horizon - line at which earth and sky appear to
meet. Its position, which can be altered by titling the camera
or by cropping the image determines whether the sky or the landscape
concentrates interest in the picture. A low horizon (tilting the
camera up) concentrates interest in the sky while a high horizon
(tilting the camera down) concentrates interest in the landscape.
Hot shoe - fitting on the top of many cameras designed
to hold accessories, such as a flash gun.
Hot spot - often undesirable concentration of the
central beam of a flood or spotlight on the subject.
Hue - name of the color (e.g. red, blue, yellow).
Hydrobromic acid - acid liberated during the developing
process by the reduction of bromide.
Hydrochloric acid - chemical used in some bleaching
Hydrogen peroxide - chemical used in hypo clearing
Hydroquinone - reducing agent.
It is used in developers to provide high contrast results in the
presence of a strong alkali.
Hyperfocal distance - distance between the camera
and the hyperfocal point.
Hyperfocal point - nearest point
to the camera which is considered acceptably sharp when the lens
is focused on infinity. When a lens is focused on the hyperfocal
point, depth of field extends from a distance halfway between
this point and the camera to infinity.
Hypersensitizing - method of increasing the light
sensitivity of a photographic emulsion prior to exposure.
Hypo - common name for a fixing agent, derived from
an abbreviation of hyposulfite of soda, the misnomer applied to
sodium thiosulfate during the 19th century.
Hypo eliminator - chemical bath which removes traces
of fixing agent from an emulsion.
Glossary - I
"Ideal" format - film format in the proportion
of 4 to 3, e.g. 6 x 4.5cm. This ratio is considered the ideal
shape by some manufacturers and many photographers for both vertical
and horizontal composition.
IF (Internal Focusing) - system in which only the
internal lens group shifts during focusing. IF benefits include
focusing without changing the physical length of a lens body,
faster focusing, reduced diameter of the focusing ring, closer
minimum focusing distance, and aberrations corrected throughout
the entire focusing distance range.
Illuminance - term quantifying the illumination
of, or incident light falling on a surface.
Image - two dimensional representation of a real
object, produced by focusing rays of light.
Image plane - plane commonly
at right angles to the optical axis at which a sharp image
of the subject is formed. The nearer the subject is to the camera,
the greater the lens image plane distance.
Impressionism - art movement in which painters broke
away from the techniques of continuous brushstrokes and clearly
expressed detail. They were largely concerned with the effects
of light and color.
Incident light - light falling
on a surface, as opposed to reflected by it.
Incident light attachment - accessory for a hand
held exposure meter which allows it to give incident light readings.
Many models come with this accessory permanently attached.
Incident light reading - measurement, by light meter,
of the amount of incident light
falling upon a subject. The light meter is placed close to the
subject, pointing towards the main light source.
Indicator chemical - neutral chemical which can
be added to a sample of a solution to indicate its pH level or
the presence of hypo.
Infectious development - development action which
occurs in processing "lith" materials. The oxidation
of hydroquinone produces new
and highly active reducing agents, semiquinones, in the presence
of a low quantity of sodium sulfite. This results in a very high
Infinity - in photographic terms
is a distance great enough to be unaffected by finite variations.
In practice this relates to most subjects beyond 1000 meters or,
in landscape terms, the horizon.
Infrared - rays that occur beyond
the red end of the electro-magnetic spectrum and are invisible
to the human eye. They can be recorded on specially sensitized
films, producing images in black & white or color.
Infrared compensation index - used to compensate
the focus for black and white infrared film. Color IR film generally
does not require compensation.
Infrared focus - see IR
Instamatic camera - compact camera popular in the
1960s and 70s with very simple controls, taking 126 film and yielding
a 28 x28 mm negative.
Instant picture camera - camera, usually with simple
controls, producing a finished photographic print within minutes
of the film being exposed, (e.g. Polaroid cameras and materials).
Integral tri-pack - three emulsions, usually of
different character, coated on the same film base. The system
is used mainly on color materials and also on some special purpose
black & white materials.
Integrating - term used to describe a method of
arriving at an exposure setting by taking an average of the light
readings from the bright areas and the and the shadow areas of
Intensification - chemical method
of increasing the density of the photographic image. It is only
suitable for treating negative materials and works better on negatives
that have been underdeveloped rather than underexposed.
Intensity scale - exposure scale in which the time
of exposure remains constant but the intensity of light increases
in regular stops.
Interchangeable lens system - system of lenses of
different focal lengths made to fit the same camera body.
Interference - interaction of light waves when they
meet and either reinforce or cancel each other (e.g. holograms).
Interleaving - method of agitating more than one
sheet of photographic paper in the same tray of chemicals.
Intermittency effect - states that, a number
of short, separate exposures will not produce the same photographic
result when combined as a single exposure of equivalent total
Internegative - negative made on special color film
designed for making copy prints from color slides.
Intersection of thirds - compositional technique
whereby the image area is divided horizontally and vertically
into equal thirds by means of four imaginary lines. The main subject
is considered strongly placed it it is positioned at the intersection
of any two of these lines.
Interspersed aspect ratio - basic requirement of
certified photofinishers and certified photo finishing equipment.
It specifies the three APS system print formats - C, H and P.
Inverse square law - states that, when the
light source is a point, illumination on a surface is inversely
proportional to the square of the distance of the light source.
Inverted telephoto lens - lens construction which
gives a short focal length with a long back focus or lens-film
distance. It enable wide-angle lenses to be produced for small
format cameras, where space is required for mirrors, shutters,
Iodine - chemical used in reducers and bleachers.
Iris diaphragm - continuously adjustable lens aperture
consisting of interposed metal leaves.
Irradiation - by the physical structure of
the emulsion and the distribution of the silver halide grains
cause rays of light to be scattered as they travel through the
IR setting - mark usually in
red, found on many camera lens mounts. It indicates the focus
change required for infrared
IS (Image Stabilizer) - feature that minimizes the
effects of camera shake. Originally designed for video cameras.
Canon has transferee the technology to its EF lenses.
I setting - mark found on some cheap box cameras
which indicates an instantaneous shutter speed of approximately
ISO - International Standards
Organization. Used instead of ASA as prefix to film speeds. The
scale is identical to the ASA scale.
Ivorytype - obsolete printing process designed to
give the impression of a painting on ivory. A hand colored print
was impregnated with wax and squeegeed face down on hot glass.
The paper base was then back by ivory tinted paper.
IX (Information Exchange) - ability of APS film
to communicate with devices, and devices to communicate with film.
Glossary - J
JCII - Japan Camera Inspection and Testing Institute.
It is an organization in Japan to monitor export quality of Japanese
JPEG - format for compressed
graphics files. JPEG graphics are commonly used as part of World
Joule - unit used to quantify
the light output of electronic flash. A joule is equal to one
watt second of 40 lumen-seconds. The measure is used to compare
flash units in terms of power output.
Glossary - K
K14 - Kodak's chemical process for developing Kodachrome
Kallitype - obsolete printing
process, resembling the platinum process. The image is formed
in metallic silver rather than expensive platinum.
Kelvin (K) - unit of measurement
on the absolute temperature scale, used to describe the color
content of continuous spectrum light sources.
Kerr cell - high speed shutter without moving parts,
using two crossed polarizing filters at either end of a cylinder
filled with nitrobenzine.
Keyed emulsion sensitivity - term used to describe
the color response of color printing papers which have peak sensitivities
to the three dye colors present in the same manufacturers color
Key light - studio light used
to control the tonal level of the main area of the subject.
Kilowatt - unit of 1000 watts. Used to measure the
power of an electrical light source.
Kinetic - concerned with movement and motion.
Knifing - method of removing marks and other blemishes
from the surface of a print by gentle scraping with the tip of
a sharp knife.
Kostinsky effect - development effect in which dense
image points are inclined to move apart, relative to each other,
and light image points to move together, relative to each other.
This occurs because developer is not being equally distributed
over the image point and is rapidly exhausted when to heavily
exposed image points are close together.
Kromskop - early viewing instrument invented by
F.E. Ives, embodying a system of mirrors and color filters to
synthesize a full color image. This enabled monochrome transparencies
made from separation negatives to be rear-illuminated through
blue, green and red filters, and then been seen combined in register
as a single image.
Glossary - L
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
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
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
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
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
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
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
Long focus - a lens in which the focal length is
much greater than the diagonal of the film format with which it
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
Luminosity - brightness of either
a light source or a reflective surface.
Luminous flux - intensity of a light source, measured