A Glossary of Photographic Terms H- M
Halation
Is a 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 image.
Halo
A light line around object edges in a image, produced by the USM (sharpening)
technique.
Hanger
A frame for holding sheet film during processing in a tank.
Hard Developer
A paper developer that can be used alone or in combination with other developers
(two-bath development). When used alone, a hard developer can produce a wide
range of tones. Contrast can be varied by changing paper grades, changing filtration,
or using a softer developer to obtain intermediate contrast grades.
(See paper types: variable contrast, graded contrast, resin coated, fibre based.)
Hardeners
Are chemicals often used with a fixing bath to strengthen the physical characteristics
of an emulsion. The most common hardeners are potassium or chrome alum.
H&D curve
Another name for the D/log E curve, after its originators, Ferdinand Hurter
and Vero C. Driffield.
High Contrast
A wide range of density in a print or negative.
High key
A light image that is intentionally lacking in shadow detail.
Highlights
The whitest or brightest part of an image; the opposite of shadows.
Highlight Separation,
Highlights
Important bright areas (highlights) of a scene in which detail must be recorded
(exposed) onto the film. Highlights are represented on a negative by dense deposits
of black metallic silver, reproducing as the bright areas on a print. (Also
see shadow detail.)
Honeycomb
Grid which makes light from a flash (or other source) more directional, like
a spot rather than a flood.
Hot Shoe
The fitting on a camera that holds a small portable flash. It has an electrical
contact that aligns with the contact on the flash unit's "foot" and
fires the flash when you press the shutter release. This direct flash-to-camera
contact eliminates the need for a PC cord.
Hot-spot
Concentration of light in a particular area.
Hue
The aspect of colour that distinguished it from another colour (what makes a
colour red, green, or blue). Hue is distinct from saturation, which measures
the intensity of the hue.
Hyperfocal Distance
Distance of the nearest object in a scene that is acceptably sharp when the
lens is focused on infinity.
Hypo
The name for a fixing bath made from sodium thiosulfate, other chemicals, and
water; often used as a synonym for fixing bath.
Hypo Clear
Chemical solutions used to speed up the efficient removal of fixer from the
prints in subsequent water washings of the prints.
Image plane
Is the 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.
Incandescent lamp
An electrical lamp in which the filament radiates visible light when heated
in a vacuum by an electrical current.
Incident Light
Light falling onto a surface, not reflected from it (reflected light).
Incident meter
A hand-held Exposure meter that measures the intensity of light falling on the
subject. To use it, you usually aim the hemispheric dome toward the camera.
Most incident meter can also be used in a mode to measure reflected light.
Indoor film
Film formulated to give correct colour rendition when photographing subjects
under 3200K light. It is also called "tungsten" film. Most film is
balance for daylight and if you use daylight film with household lamps or photographic
lamps, the colours will be slightly reddish or orange. The light from an electronic
flash is similar in colour rendition to daylight.
Infinity
In photographic terms is a distance great enough to be unaffected by finite
vibration. In practice this relates to most subjects beyond 1000 meters or in
landscape terms, the horizon. When the infinity distance is within the depth
of field all objects at that distance or farther will be sharp.
Infrared
The region of the electromagnetic spectrum adjacent to the visible spectrum,
just beyond red with longer wavelengths.
Integration
Integration in photographic analysis is defined as the method of averaging all
density ( illumination ) values either in R, G, and B, or as neutral density
and saving this aggregate value to determine exposure in the camera or the darkroom.
Intensity
The relative brightness of a portion of the image or illumination source.
Inter-negative
A negative created directly from a colour-reversal (positive) or black-white
positive film. It is the negative copy of the camera original.
Inter-positive
A positive transparency image generated as an intermediate step to enlarge an
image in positive form either from a negative or positive material.
Inverse square law
A law of physics that states that light from a point source fall off inversely
to the square of the distance. As a example, if a light is 10 feet from your
subject and you move it to 20 feet, you'll only have 1/4 the lighting intensity.
If you move the light to 40 feet, it will now have only 1/16th the intensity.
Inverting
Creating a negative of an image
ISO Speed
The emulsion speed (sensitivity) of the film as determined by the standards
of the International Standards Organization. In these standards, both arithmetic
(ASA) and logarithmic (DIN) speed values are expressed in a single ISO term.
For example, a film with a speed of ISO 100/21° would have a speed of ASA
100 or 21 DIN.
K 14
Kodak's chemical process for developing Kodachrome slides.
K (Kelvin)
Abbreviation for Kelvin temperature, the measurement of the redness or blueness
of white light. This is written without the degree sign. Daylight at noon, for
example, has a Kelvin temperature of about 5500K, while photographic tungsten
lamps are 3200K. Technically it is a measurement of the colour of white or grey
based on the temperature to which a black body must be heated to produce that
colour of white.
Key light
A studio light used to control the tonal level of the main area of the subject.
Key-stoning
Distortion of a projected image when the projector is not directed perpendicular
to the screen.
Lamp
A general term used to describe the various kinds of artificial light sources
used in photography.
Lantern slides
Is a old term used to described transparencies.
Large format camera
Is a general term for any camera having a picture format of 4x5 inches or larger.
Latent Image
The invisible image left by the action of light on photographic film or paper.
The light changes the photosensitive salts to varying degrees depending on the
amount of light striking them. When processed, this latent image will become
a visible image either in reversed tones (as in a negative) or in positive tones
(as in a colour slide).
Lateral reversal
A mirror image, as seen in the viewfinders of some cameras where the scene appears
flipped from left to right.
Latitude
Is the 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 panel
Liquid Crystal Display on cameras that shows such information as remaining exposures,
flash status and aspect ratio selected.
Leaf shutter
A camera mechanism that admits light to expose film by opening and shutting
a circle of overlapping metal leaves.
Lens
One or more pieces of optical glass or similar material designed to collect
and focus rays of light to form a sharp image on the film, paper, or projection
screen. A lens made of a single piece of glass cannot produce very sharp or
exact images, so camera lenses are made up of a number of glass "elements"
that cancel out each other's weakness and work together to give a sharp true
image. The size, curvature and positioning of the elements determine the focal
length and angle of view of a lens.
Lens aperture (f/)
The physical opening of a lens. The smaller the f/number the more light passes
through.
Lens barrel
A metal or plastic tube with a blackened inner surface, in which the lens elements
and mechanical components of the lens are mounted.
Lens cap
Is a plastic, rubber or metal cover which fits over the front or back of the
lens to protect it.
Lens coating
A layer or multiple layers of thin anti-reflective materials applied to the
surface of the lens elements to reduce light reflection and increase the amount
of transmitted light.
Lens Shade
A collar or hood at the front of a lens that keeps unwanted light from striking
the lens and causing image flare. May be attached or detachable, and should
be sized to the particular lens to avoid a vignette.
Lens-Shutter Camera
A camera with the shutter built into the lens; the viewfinder and picture-taking
lens are separate.
Lens Speed
The 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.
Light-box
A box of fluorescent tubes balanced for white light and covered with translucent
glass or plastic. Used for viewing, registering or correcting prints , film
negatives and positives.
Light meter
Is an alternate term for exposure meter.
Light sources
A general term applied to any source of light used in photography.
Lighting ratio
The ratio between the key and fill lights.
Light-tight
Refers to any room or containers that is absolutely dark inside, allowing no
unwanted light to penetrate.
Line art copy
Images containing only black and white pixels. Line art may also include one-colour
image, such as mechanical blue prints or drawings.
Lithium
Some of the newer digital cameras are now coming with a lithium rechargeable
battery pack. Lithium batteries are lighter and more costly than NiMH or NiCad
type of rechargeable cells and can be rapidly charted.
Lith film
A type of film made primarily for use in graphic arts and printing. It produces
an image with very high contrast.
Low key
A dark image that is intentionally lacking in highlight detail.
Luminance
Lightness. The highest of the individual RGB values plus the lowest of the individual
RGB values, divided by two; a component of Hue-Saturation- Lightness image.
Luminosity
The brightness of either a light source or a reflective surface.
Lux
A measurement of the light intensity. One Lux in video means light level of
a candle light. l Lux approximately equals to 10 foot-candles (1 Lux = 10.764
fc).
Macro attachment
These are supplementary elements attached to the front of a normal lens to give
an extreme close-up facility.
Macro Lens
A lens that provides continuous focusing from infinity to extreme close-ups,
often to a reproduction ratio of 1:2 (half life-size) or 1:1 (life-size).
Magazine
A light tight metal container (cartridge) that holds 135 film (cylindrical magazine).
Main light
Same as " Key light " the principal source of light, usually in a
studio, and generally the brightest light on a subject or scene.
Manual exposure
A mode of camera operation in which all exposure settings are determined and
set by the photographer.
Mid tones
An area of medium brightness, neither a very dark shadow not a very bright highlight.
A medium grey tone in a print.
Mini-lab
Photo-finishing operation that operates on a retail level, serving consumers
directly and processing film on-site.
Modeling light
A light built into a flash unit that remains on while the flash is turned or
on standby mode, permitting the photographer to assess highlight and shadow
areas that will be created when subsequently exposing the film in the brighter
light of the flash.
Mono bath
Is a single solution which combines developer and fixer for processing b&w
negatives. It is a quick simple system but does not allow for development control.
Monochrome
Single-coloured. An image or medium displaying only black and white or greyscale
information. Greyscale information displayed in one colour is also monochrome.
Monopod
A one-leg stand for holding the camera steady.
Monorail
Large format camera (usually, though there are medium format examples) constructed
on an " optical bench " principle with front and rear standards on
a rail.
Motor Drive
A mechanism for advancing the film to the next frame and re-cocking the shutter,
activated by an electric motor usually powered by batteries. Popular for action-sequence
photography and for recording images by remote control.
Mounting press
Also called a dry-mounting press. A device that provides both pressure and heat,
for mounting a photograph on a support, using a tissue coated with heat-softenable
adhesive.
Mounting tissue
Also called mounting tissue. A thin paper coated with adhesive on both sides
for permanently adhering a photograph to a support. The adhesive is softened
by heat and hardens when it cools.
Movements
Large format camera movements to help focus, shape, composition or converging
angles (swing, shift & tilt ).
Multiple exposure
More than one exposure on the same frame of film. Called a " Double-exposure
" when there are two exposures on a single film frame.
