Photography glossary - C

C-41 - Standard chemical process for developing color
negative film.

Cable release - flexible cable used for firing a camera shutter.
Particularly useful for slow shutter speeds and time exposures,
when touching the camera may cause camera vibration and
blurring of the image.

Cadmium sulfide cell (CdS) - photo-sensitive cell used in
exposure meters. Fed by an electric current from a battery, its
electrical resistance varies according to the amount of light it
receives.

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Callier effect - contrast effect in photographic printing caused by
the scattering of directional light from an enlarger condenser
system. The negative highlights are of high density and scatter
more light with little or no scattering from negative shadow areas,
which are of low density. This gives a print higher contrast than a
contact print.

Calotype process - first negative/positive process, invented by
W.H. Fox Talbot in 1839. Paper was coated with silver iodide and
a solution of silver nitrate and gallic acid. After exposure the paper
was developed in a silver nitrate solution.

Calibration - The reciprocal balancing or tuning of input and output devices, in order to receive a matching value. In this way, the colours on a monitor can be matched with the printer''''''''''''''''s colours.

Camera angles - various positions of the camera with respect to
the subject being photographed, each giving a different viewpoint
and perspective.

Camera lucida - lens and prism system through which a virtual
image was seen, apparently appearing on the surface of the
drawing paper.

Camera movements - mechanical systems most common on
large format cameras which provide the facility for lens and film
plane movement from a normal standard position.

Camera obscura - origin of the present day camera. In its
simplest form it consisted of a darkened room with a small hole in
one wall. Light rays could pass through the hole to transmit on to a
screen, and inverted image of the scene outside. It was first
mentioned by Aristotle in the 4th Century B.C. and developed
through the centuries as an aid to drawing.

Camera shake - movement of the camera caused by an unsteady
hold or support. It is a major cause of un-sharp pictures, especially
with long focus lenses.

Canada balsam - liquid resin with a refractive index similar to
glass. It is used for bonding elements in compound lenses.

Candela - unit which expresses the luminous intensity of a light
source. 1 cd is 1/683W per steradian.

Candid pictures - unposed pictures of people and animals, often
taken without the subject''''''''''''''''s knowledge. These usually appear more
natural and relaxed than posed pictures.

Candle meter - also known as a lux and defined as the
illumination measured on a surface at a distance of one meter from
a light source of one international candle power.

Candle meter second - unit of illumination related to exposure
time, more often referred to as one lux-second.

Capacitor - device that builds and stores electrical charges. Used
in electronic flash and some forms of electronic shutters.

Capping shutter - extra shutter used in some medium format
cameras or in conjunction with a group of extreme high speed
shutters.

Caption - Words describing the scene or action in an image. Caption can be written in to the file, Follow a print or be in a xmp side-car. Caption is often part of Meta Data.

Capture A term used in digital imaging meaning " to photograph". The term is used to differentiate the method by which the image is made. As the word "photograph" is closely associated to film photography, "capturing" is applied to specify a digital sensor is used."

Carbon arc - see Arc lamp.

Carbon process - contact printing process, introduced in 1866,
using tissue coated with pigmented gelatin. The paper was
sensitized in potassium bichromate and contact printed behind a
negative in sunlight.

Carbon tetrachloride - liquid used for removing grease and finger
prints from negatives.

Carbro process - early color print process using an adaptation of
the carbon printing process.

Card A sealed package containing storage chips or other electronic devices for use in a card slot on a camera, printer, computer, or other device.

Card Reader A device, which allows your computer to directly, read flash memory cards. See also PCMCIA and PC Card

Carrier - frame that holds a negative flat for enlarging.

Carte-de-visite - portrait photograph on a mount about the size of
a postcard. Introduced in 1854, carte-de-visite became a social
craze in many countries during the 1860s.

Cartridge - quick loading film container. pre-packed and sealed
by the manufacturer.

Cassette - light tight metal or plastic container holding measured
lengths of 35mm or medium format film, which may be loaded
straight into the camera.

Cast - overall bias toward one color in a color photograph.

Catadioptric lens - see Mirror lens.

Catchlight - reflection of a light source in the subjects eyes.

Cathode ray tube - evacuated bulb of glass containing pairs of
plates between which electrodes pass.

Caustic potash - high alkaline used in high contrast developing
solutions to promote vigorous development. Highly corrosive and
poisonous.

Caustic soda - see Caustic potash.

CCD - Charge-Coupled Device. one of the two main types of image sensors used in digital cameras. When a picture is taken, the CCD is struck by light coming through the camera''''''''''''''''s lens. Each of the thousands or millions of tiny pixels that make up the CCD convert this light into electrons. The number of electrons, usually described as the pixel''''''''''''''''s accumulated charge, is measured, then converted to a digital value. This last step occurs outside the CCD, in a camera component called an analog-to-digital converter.
CC filter- abbreviation for color compensating filter.CC filters are
designed primarily for introducing or correcting color bias at the
camera exposure stage.

CD-ROM - Compact-Disc-Read-Only-Memory. A "read only" CD-ROM can hold up to approximately 700 MB of programs, pictures, text, or other data.

CDRW (CompactDisc ReWriteable) A CD-R that can be erased and re-used many times, which holds about 450 MB of data.

Centre - weighted metering
Is a method of exposure metering that lays most impact of light metering the center subject of an image.

Centigrade - scale of temperature in which the freezing point of
water is equal to 0° and boiling point to 100° C.

Center Weighted An autoexposure system that uses the center portion of the image to adjust the overall exposure value. See Spot Metering and Matrix Metering

Changing bag - opaque fabric bag, which is light tight and inside
sensitive materials may be handled safely.

Charger - Battery-charger.

Characteristic curve - performance graph showing the
relationship between exposure and density under known
developing conditions. It can provide immediate comparative
information on factors such as emulsion speed, fog level, and
contrast effect. The study of photographic chemicals in this way is
known as sensitometry.

Chemical focus - point at which a lens brings the actinic rays to
focus. In a modern fully corrected lens, chemical and visual focus
coincide.

Chemical fog - even, overall density on film or paper. It is
exaggerated by over-development.

Chemical reducer - see Reducers.

Chemical vapor - method of exposing negatives in a closed
container to a small amount of mercury of sulfur dioxide. After
approximately 24 hours the film is developed normally. It produces
interesting yet very inconsistent results.

Chip - General description for integrated circuits whose components (e.g. transistors, diodes, resistors) are mounted on a small plate of the semiconducting material silicon.

Chiaroscuro- light and shade effect. The way in which objects
can be emphasized by patches of light, or obscured by shadow.

Chlorhydroquinone - developing agent contained in warm tone
developers.

Chloride paper - printing paper with a silver chloride emulsion.
Much less sensitive than bromide paper. Mainly used for contact
printing.

Chlorobromide paper - photographic paper coated with an
emulsion made up of both silver chloride and silver bromide. Used
for producing enlargements with a warm, slightly brownish-black
image, especially if processed in a warm tone developer.

Chlorquinol - alternate term for chlorhydroquinone.

Chrome - See color transparency

Chromatic aberration - A fringing effect around the edges, which is caused by lens not focusing correctly.

Chromaticity - objective measurement of the color of an object or
light source.

Chromatype - early type of extremely slow paper used for contact
printing.

Chrome alum - alternative term for potassium chromium sulfate.

Chromogenic development - process in which the oxidation
products of development combine with color couplers to form dyes
during processing.

Chromogenic materials - color photographic materials which
form dyes during processing.

Chronocyclograph - photograph used for the analysis of complex
cyclic movements.

Chronophotography - technique pioneered by Eadweard
Muybridge, for recording objects in motion by taking photographs
at regular intervals.

Cibachrome - color printing process that produces color prints
directly from color slides.

CIE standard - system of standards adopted by the Commission
Internationale de I''''''''''''''''Eclairage, allowing accurate descriptions of
colors. The set standards are the basis for the colour definition in DTP standards.

CIFF (Camera Image File Format) A method of digital camera image storage used by many camera makers.

CISC - ComplexInstruction Set Computer. A type of processor that recognises and processes a large number of complex and powerful instructions without the need for additional software.

Circle of confusion - disks of light on the image, formed by the
lens from points of light in the subject. The smaller these disks are
in the image the sharper it appears.

Clayden effect - desensitizing of an emulsion by means of
exposure to a strong, brief flash of light.

Clearing agent - processing solution used to remove stains or to
cancel out the effect of chemicals left on the sensitive material left
from previous stages in the process.

Clearing time - length of time needed for a negative to clear in a
fixing solution.

Clear-spot focusing - method of lens focusing achieved by
examining the image through a transparent area in a specific
plane.

Cliche-verre - designs painted on glass in varnish or oil paint, or
scratched into the emulsion of a fogged and processed plate using
an etching needle. The results are then printed or enlarged on
photographic printing paper.

Click-stops - lens aperture controls using a series of bearings
that click audibly into place at each numbered setting.

Clip test - short sample of film, cut from the main exposed roll,
used to determine the appropriate development and/or fixing time.

Close-up - general term for an image of a close subject, i.e. filling
the frame.

Close-up attachment - accessory that enables a camera to focus
on subjects nearer than the lens normally allows.

Close-up lens - see Close-up attachment.

CMOS (Complementary Metal Oxide Semiconductor) An imaging system used by digital cameras.
Codec (Compression and Decompression) Compresses information so that it can be sent across a network faster, and decompresses information received via the network.

CMYK - abbreviation for cyan, magenta, yellow and black. It is the
colors used in a four color printing process. Subtractive colour mixing

CPU - Central Processing Unit. The main processor of a PC (personal computer).

Coated lens - lens with air-glass surfaces which have been
coated with magnesium fluoride to reduce lens flare.

Coherent light - light waves that vibrate with constant phase
relationships. They can be produced by a laser or a combination of
two prisms.

Coincidence rangefinder - see Rangefinder.

Cold cathode illumination - low temperature fluorescent light
source common in many diffuser enlargers, which is inclined to
reduce contrast and edge definition.

Cold colors - colors at the blue end of the spectrum that suggest
a cool atmosphere.

Cold-light enlarger - enlarger using cold cathode illumination. A
diffusion type of enlarger. These types of enlarger heads scatter
the light more evenly across the surface of the negative. One
advantage of the cold light head is that it can render more subtle
tonal gradations and will minimize the effect of dust and scratches
on the negative which are translated to the print.

Collage - composition employing various different materials
combined with original artwork attached to some type of backing.

Collodion - soluble gun-cotton, dissolved in a mixture of ether
and alcohol.

Collodion process - also known as "wet collodion" was invented
by Frederick Scott Archer in 1851-52. It was a great improvement
over the earlier calotype process because because of the large
increase in speed gained by exposing the plate while still "wet", but
it had the disadvantage of requiring bulky equipment.

Color balance - adjustment in color photographic processes
ensuring that a neutral scale of gray tones is reproduced accurately.

Color balancing filters - filters used to balance color film with the
color temperature of the light source and prevent the formation of
color casts.

Color circle - chart of spectrum hues presented as a circle.

Color compensatory filters - pale colored filters used to warm or
cool subject colors.

Color contrast - subjective judgment on the apparent luminous
difference or intensity of two colors when placed close to one
another.

Color conversion filter - see CC filters.

Color correction Adjustments made to an image to compensate for digital input and output characteristics.

Colour depth - This refers to the maximum number of colours that can be recorded by digital cameras and scanners or can be displayed by graphics cards. A true colour representation can be achieved at a colour depth of 8 bits per primary colour, that is a 24 bit colour depth. In this case, 256 bits are available for one pixel. With an RGB signal, this value is then multiplied by a factor of three so that a total of 256 x 256 x 256 = 16,777,216 colours can be displayed. High-end scanners, graphic cards etc. provide a minimum colour depth of 24 bit.

Color developer - developer designed to reduce exposed silver
halides of black silver and at the same time create oxidation
byproducts that will react with color couplers to form specific dyes.

Color development - chemical treatment in the color processing
cycle that produces the colored dye image.

Color-Filter Array The filter dyes placed directly over each pixel on the chip surface (CCD, CMOS).

Color head- enlarger illumination system that has built-in
adjustable filters for color printing.

Color masking - pink or orange mask built into color negative film
to improve final reproduction on the print.

Color mixing - practical application of either additive or
subtractive color synthesis.

Colour management - The calibration of all peripheral devices that feature in the production of colour images (monitors, scanners, colour printers etc.). For example, by using a colour management system, the data from a scanner is converted into values for a standard colour range. The data is then arranged so that the printer can produce good colour prints.

Colour noise - The incorrect reproduction of colour on n image (e.g. dots on an area which is supposed to be pure white).

Color Negative - film designed to produce color image with both
tones and colors reversed for subsequent printing to a positive
image, usually on paper.

Color reversal - film designed to produce a normal color positive
image on the film exposed in the camera for subsequent viewing
by transmitted light.

Color saturation - purity or strength of color, due to the absence
of black, white or gray.

Color sensitivity - response of a sensitive material to colors of
different wavelengths.

Color sensitometry - method of determining the sensitivity of
color materials.

Color separation - process of photographic an image through
filters to produce three black and white negatives that represent
red, green and blue content.

Color synthesis - combinations of colored light or dye layers that
will collectively produce a colored image.

Colour temperature - Describes the spectral energy distribution and thereby the colour quality of a light source. The temperature of a colour is given in Kelvin (K). It is important to choose the correct temperature so that a subject can be photographed in its true colours. The spectrum that can be seen by the human eye lies between approx. 2,790 K and 11,000 K. The international norm for average sunlight is 5,500 K

Color temperature meter - device for measuring the color
temperature of a light source.

Color toning - system of changing the color of a black and white
photograph by converting black metallic silver into a colored
compound.

Color weight - visual characteristic of fully saturated colors. Some
of these colors appear darker than others. A color''''''''''''''''s visual weight
may have a different appearance to the eye to its appearance on
film.

Compatibility - The ability of data, programs (software), and equipment (hardware) to run and/or work together. This allows for the individual components to be put together to form a system.

CompactFlash card - Rewritable removable memory or function card developed by SanDisk in 1994.
CF Type I: the original 5mm high card
CF Type II: cards and devices that are 9mm high. Type I devices are all solid state but Type II
devices include the new IBM Microdrive, a miniature, rotating hard drive. and check here: Flash
Memory Cards/Readers
CF Type III: used in double-height slots only.

Coma - lens aberration producing asymmetrical distortion of points
in the image.

Combination printing - producing a composite image by printing
more than one negative on a single sheet of paper.

Commission - Fee charged by photo agent, image gallery or stock image agency for finding a buyer to a image or assignment.

Compact camera. - Smaller dimensions and reduced weight make these easy to handle cameras ideal for travel and everyday use..

Compensating developer - developer designed to compress the
general contrast range in a negative without influencing gradation
in the shadow and highlight areas.

Compensating positive - image on translucent material that can
be printed together with the negative of the same image. When
combined the result makes printing contrasty negatives easier.

Complementary color - color of light which, when combined with
another specified color in the correct proportions, will form gray or
white.

Completion - state of development when all the exposed silver
halides have been reduced to metallic silver, and the image density
will not increase with further development.

Composite printing - alternative term for combination printing.

Composition - visual arrangement of all the elements in a
photograph.

Compound lens - lens system consisting of two or more
elements. Compound lens designs can allow the lens designer to
reduce lens aberrations, making maximum apertures larger and
improve resolution.

Compound shutter - shutter consisting of a number of metal
leaves arranged symmetrically around the edge of the lens barrel.

Compur shutter - well known German brand of compound
shutter.

COM port - Describes the serial interface of a computer. Often used to connect devices such as digital cameras to a computer.

Compression - The process of reducing the size of a file. Compression is either lossless or lossy. Data may be compressed to reduce storage (memory) space or transmission times (= reducing the amount of data). Wellknown compression standards include JPEG and MPEG.

CompuServe - Commercial data service that offers countless information and discussion panels about an unlimited variety of subjects.

Computer controlled flash - Almost all compact or grip-type flashes are computer controlled. They set their intensity by directing a sensor at the subject, thus gathering the information from which the flash output can be attained. The light sensor often gathers the data through the cameras lens.

Concave lens - see Bi-concave lens.
Condenser - optical system which concentrates light rays from a
wide source into a narrow beam. Condensers are used in
spotlights and enlargers.

Condenser enlarger - enlarger with a sharp, undiffused light that
produces high contrast and high definition in a print.
Cones - sensory organs on the retina of the eye, allowing color
vision.

Constructivism - art movement that begun in Russia c. 1913.
Characterized by the use of everyday materials in abstract
compositions.

Consumer publication. - Magazines of general interest sold on news stand or by subscription.

Contact sheet - A sheet of negative sized images made by placing the negative in direct contact with the printing paper during exposure.

Contact paper - printing paper used only for contact printing. It is
usually coated with a silver chloride emulsion of very slow speed.

Contact print - negative sized photograph made by exposing
printing paper in direct contact with the negative.

Contact printer - apparatus used for making contact prints.
Equipment ranges from a contact printing frame to more
sophisticated boxes with safe lighting.

Contact screen - type of half-tone screen in which the dots
consist of slightly unsharp halos. Used to make half-tone images.

Contamination - traces of chemicals that are present where they
don''''''''''''''''t belong.

Continuous Autofocus An always-on autofocus system.

Continuous tone - term applied to monochrome negatives and
prints, where the image contains a gradation of density from white
through gray to black, which represents a variety of subject
luminosities.

Contour film - special print film producing a equidensity line
image from a continuous tone negative or print.

Contrast - subjective judgment of the difference between densities
or luminosities and their degree of tonal separation in a subject. Increasing contrast for an image effectively reduces it''''''''''''''''s Dynamic Range (DR) but gives it a more pleasing appearance (to an extent) by
increasing the noticeable different between tones. Reducing the contrast has the opposite effect.

Contrast filters - filters used in black and white photography to
darken or lighten the films rendition of particular colors in the
subject.

Contrast grade - numbers (usually 1-5) and names (soft,
medium, hard, extra-hard, and ultra hard) of the contrast grades of
photographic papers.

Contrast values - perceived difference between the light areas
(highlights) and the dark areas (shadows) of a scene. The range of
contrast levels between the highlights and the shadows is called
Contrast Values.

Contrasty- negative, print or scene with great differences
between the highlights and shadows.

Contre-jour - backlighting. A photograph taken with the camera
pointed directly at the light source.

Converter/ Lens converter - Lens extension that increases or shortens the focal distance.

Converging lens - see Convex lens.

Convertible lens - compound lens made in two sections, the
elements of which are arranged so that when one part is
unscrewed it provides a new lens with approximately twice the
original focal length.

Convex lens - simple lens which causes rays of light from a
subject to converge and form an image.

Cooke triplet - one of the most important lenses in lens history,
designed by H.D. Taylor in 1893. It consists of three basic
elements and has a maximum aperture of 16.3. It is the basic
design that most normal focal length lenses of today have evolved.

Copper chloride - chemical contained in certain bleaches, toners,
intensifiers, and reducers.

Copper sulfate - chemical contained in certain bleaches, toners,
intensifiers, and reducers.

Copper toning - chemical process used for toning monochrome
prints. See Toners.

Copyright - The exclusive legal right to reproduce, publish and sell the matter and form of an artistic work.

Copyright laws- laws which govern the legality of ownership of a
particular photographer or piece of work.

Correction filter - filter which alters the color rendition of a scene
to suit the color response of the eye.

Coupled rangefinder - system of lens focusing which combines
the rangefinder and the focusing mechanism, so that the lens is
automatically focused as the rangefinder is adjusted.

Coupler - chemical present in different forms in all three layers of
substantive color or a chemical incorporated into a developer.

Covering power - maximum area of image of usable quality,
which a lens will produce.

Coving - plain curved background which has no edges, corners
or folds and gives the impression of infinity.

CP filters - abbreviation for color printing filters.

C-print - any enlargement from a color negative.

CRT - Cathode Ray Tube. Electron guns inside the tube send beams onto the front surface of the tube, causing it to glow and creating a display.

Credit line - The byline of photographer or organization that appears below or beside a published photograph

Critical aperture - setting at which a lens gives its best
performance. The setting offers the best compromise between
diffracting due to small aperture and lens aberrations apparent at
wide apertures.

Cronographic camera - camera used to photograph the sun.

Cropping - omitting parts of an image when making a print or
copy negative in order to improve the composition of the final
image.

Crossed polarization - system of using two polarizing filters, one
over the light source and one between the subject and the lens.
With certain materials crossed polarization causes bi-refringent
effects which are exhibited as colored bands. Used in
investigations of stress areas in engineering and architectural
models.

Cross front - camera movement which allows the lens to be
moved laterally from its original position.

Crown glass - low dispersion optical glass.

Cubism - early twentieth century European art movement
characterized by the rendering of forms as simplified planes, lines
and geometric shapes.

Curvilinear distortion - combination of barrel distortion and
pincushion distortion.

Curvature of field - lens aberration causing a curved plane of
focus.

Cut film - negative film available in flat sheets. The most common
sizes are 4x5, and 8x10 inches.

Cyan - blue-green subtractive primary color which absorbs red
and transmits blue-green.

Cyanotype - contact printing process producing a blue image on
a white background.

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