C
C41
The number given to a Chemical process for developing colour
negative film. (created by Kodak but adopted universally by every
other manufacturer).
Cable release
Flexible cable for firing a camera shutter. Useful for long exposures
where touching the camera release by hand could cause camera-shake
blur.
(see Exposure Shutter & Shutter
speed)
Camera Format
The size and aspect ratio of an image produced on film or digitally. Large format, medium format, or 35mm, but determined by the actual dimensions of the focal plane or image sensor. Digital capture technologies are confusing the traditional distinctions, since a small image sensor with many pixels is not necessarily better in quality than a larger sensor with less pixels.
(see Format, Large format, Medium format, Pixel & 35mm)
Camera movements
Mechanical Systems most common on large format cameras (and some
Medium Format) which provide the facility for lens and film plane
movement from a normal standard position. The movements can create
greater or lesser depth of field, and correct or distort image
shape.
(see Depth of field, Movements & Standard)
Camera obscura
For hundreds of years the camera obscura was a curiosity, consisting
of a darkened room with a small hole in one of its walls; a reduced
inverted image of the world outside was projected through the
hole onto a whitewashed wall opposite; the phenomenon was noted
by the Arabs as early as the eleventh century.
By the end of the sixteenth century Italian academics had fitted
a converging lens into the hole which produced a much brighter
and sharper picture. Artists began to use a collapsible, portable
version to reproduce perspective in their landscapes and portraits.
(see Pinhole camera)
Cast
(see Colour Balance, Colour Cast & Colour
correction)
Catadioptric lens
(see Mirror
lens)
CC filter
Abbreviation for colour compensating filter. CC filters are designed
primarily for correcting colour bias in colour photo printing.
CC2OY, for example, indicates a yellow filtration of 0.2 density.
(see Colour correction)
CCD
Charge Coupled Device (CCD). The Digital camera's 'film'; a CCD
converts light into a digital photograph of pixels. When a picture
is taken the CCD is struck by light coming through the camera's
lens; each of the millions of tiny pixels that make up the sensor
converts this light into electrons.
(see CMOS & Pixel)
CD ROM (Compact Disc)
Read only memory/media: an electro-optical data storage medium with the same physical format as an audio disc and a capacity of approximately 650-700mb of data.
(see: Megabyte)
Centre Weighted
A camera metering system which concentrates the light reading
mostly to the central portion of the viewfinder and feathering
out to the edges. Although in the hands of an inexperienced photographer
a 'Matrix' style meter will achieve more correct results many
professionals still prefer to use their cameras in manual mode
with the meter set to 'centre weighted'! Now regarded as a 'classic',
this metering system is included in all quality 35mm SLR cameras.
(see Matrix, finder, 35mm & SLR)
Changing bag
A light tight fabric bag, used for safely removing sensitive
photographic materials from film holders or backs in daylight.
Chromatic Aberration
The inability of a lens to focus different colours on the same
focal plane. Appearing as a 'colour fringe' around objects, especially
at the edges of the photograph.
Chrome
A positive transparency designed to be viewed when lit from behind. Used frequently to describe a 'positive' camera film. Large chromes are used for advertising or promotion purposes, and are sometimes known by the kodak brand name duratrans ‘durable transparency’.
(see E6, Trannie & Transparency)
Chromogenic film
Chromogenic literally means 'colour forming'. In chromogenic
films the final image is made of coloured dyes formed during
processing rather than Silver Halide. A Black & White chromogenic
film can be processed along side colour films in a C41 process.
(see C41 & Silver
Halide)
Circle of confusion
Disc of light in the image where a point on the subject is not
perfectly brought into focus. The eye cannot distinguish between
a very small circle of confusion and a true point.
"Clean & tight"
A phrase often used by photographers when describing a well composed
(clean) photo which eliminates all inconsequential items from
the photo (tight).
Clearing time
"Twice the clearing time" is a popular darkroom term.
Insufficient time in the fix causes film to appear milky. Photographers
use a film clipping in the fixer chemical to accurately time
this process, after a second clipping is 'clear' the film is
ready for washing.
(see Fix)
Clip test
A test to determine accurate development times using a small
part of the exposed film as a sample.
Close-up lens
A lens attachment used in front of the camera lens; pictures
then could be taken at a closer distance than normal.
(see Extension tubes & Macro)
CMOS
Complementary Metal-Oxide Semiconductor (CMOS). An image sensor
used in some digital cameras. Its basic function is the same
as the CCD.
(see CCD)
Coating
(see Multicoating)
Colour balance
How a particular colour film reproduces the colours of a scene.
All Colour films are formulated to be exposed by light of a certain
colour quality (daylight or tungsten). It also describes an adjustment
in colour photo processes that ensure a neutral scale of grey
tones is reproduced accurately, i.e. a grey subject will
have no colour cast or bias.
(see Daylight film & Tungsten
film)
Colour cast
Overall bias towards one colour in a colour photograph or trannie.
(see Colour Balance)
Colour correction
Filters which help balance the colour rendition of a scene to
match the colour response of the eye.
(see CC filters)
Colour Management System
A system for communicating colour reproduction information about digital images between input, display and output devices.
Improves fidelity of image reproduction when properly configured by all involved in a production workflow.
Colour Profile
Colour space information can improve colour fidelity when embedded into a digital image file and referenced within a 'Colour Management System' reproduction workflow.
Colour sensitivity
The response of a sensitive material to the colours of the spectrum
Colour Space
A three-dimensional representation of a colour profile, useful in digital imaging to understand colour performance between input, display and output devices.
(see: Colour Management System)
Colour temperature
Measured in Kelvin, expressed on a scale (i.e.3400K) this indicates
the colour content and quality of a light source light such as
a lamp.
(see Tungsten film)
Coma
A lens defect which results in points of light appearing in the
image not as points but as discs with comet-like tails.
Compact Flash
The removable CF card is a popular Digital Camera photo storage
system. Although they are larger than SD, Smart Media, XD Picture
Card and Memory Sticks 'Professional' use has made them widely
available and in very large sizes, currently up to 16 Gigabytes.
(see Memory Stick, Micro Drives, SD, Smart
Media & XD
Picture Card)
Complementary colour
The hue most opposite to a given colour. The complementaries
for blue, green and red are yellow, magenta and cyan respectively.
Composite
The act of combining two or more images. Today usually accomplished digitally using 'Photoshop'.
(see Photoshop)
Compound lens
Lens system consisting of two or more elements.
Compression
A digital file is compressed by removing redundant information. Some image file compression methods discard visual information that may degrade image quality.
(see JPEG and Lossy)
Compression Ratio
The amount of data in a digital image divided by the amount of data in a version after compression. Higher ratios indicate more compression which may degrade image quality.
(see JPEG and Lossy)
Concave lens
Simple lens, or lens shape within a compound lens, whose surfaces
curve inward. Such a lens causes light rays to diverge.
(see Compound lens)
Condenser
A simple lens system which concentrates light from a source into
a beam. Condensers are used in equipment such as slide projectors, spotlights
and enlargers.
(see Focusing Spot)
Contact print
A print made from placing the negative in 'contact' with a sheet
of photo paper and then exposed to light; the resulting "Contact
print" is the same size as the negative and therefore not
enlarged.
(see Contact printer & Enlargement)
Contact printer
Apparatus used for making contact prints. Usually just a simple
frame with a glass top to hold the negative and paper in tight
contact during exposure.
Contrast
A subjective judgment of the difference in brightness and density
between shadow and highlight areas in an image. Contrast is affected
by lighting, lens flare, film type, degree of development, enlarger
type and quality of printing.
Contrast grade paper
Graded by numbers (usually 1-5), the contrast grades of photographic
papers, enable us to obtain good prints from negatives of varying
contrasts. Use a low-numbered or soft paper with a high contrast
negative to get a print that most closely resembles the original
scene. Use a high-numbered or a hard paper with a low-contrast
negative to obtain a normal contrast print.
(see Multigrade)
Contrasty
Higher-than-normal contrast including very bright and very dark
areas. The range of density in a trannie or print is higher than
it was in the original scene.
Converging angles
This occurs when the camera is not held or supported vertically.
The vertical lines will seem to run together at the top or the
bottom of a photo. Most noticeable with photographs of tall buildings.
(see Movements, Rising front, Keystoning & Shift)
Converter
A supplementary lens that can double the length of a telephoto
lens (e.g.: 2x converter). Usually fitted between lens and camera
body.
Convex lens
Simple lens, or lens shape within a compound lens, whose surfaces
curve outward. Such a lens causes rays of light passing through
it to converge.
(see Compound lens)
Copy
Not an original. A print, neg., trannie, artwork or 2D object
copied on a copystand
(see Copystand & Dupe).
Copyright
A legal property right in an original work of any physical medium of expression, such as photographs. Copyright is more than the right to copy, the owner of copyright holds the exclusive right to reproduce, publicly display, adapt, distribute and to authorize others to do the same.
Copystand
A device that holds a 2D object square with the camera to obtain
quality copies of an original, the stand usually has lights attached.
Correction filter
A filter which alters the colour rendition of a scene to suit
the colour response of the eye.
(see Colour correction)
Coupled rangefinder
Focusing system in which a rangefinder and the lens focusing
mechanism are linked. As the lens is adjusted, the central area
of the viewfinder indicates when the lens is in focus (as found
on Leica M series Cameras).
Cove
Infinity cove. Found in most large studios and painted white,
a solid background that wraps over the floor & walls to create
the illusion of an infinite 'white'.
(see Background paper)
Covering power
The maximum area of usable image quality which a lens will produce.
Known as the angle of coverage. (Frequently a required knowledge
when using a large format camera with "movements").
(see Movements)
Cropping
Printing or using only part of the image that is in the original
negative or trannie, usually for a more pleasing composition.
Could also refer to the framing of the scene in the viewfinder.
(see Clean & Tight)
Cross process
To develop a film in the wrong process (e.g.: neg.(C41) film
in trannie(E6) chemicals) to obtain a sometimes bizarre colour
or contrast effect.
(see C41& E6)
Curvature of field
Lens aberration causing the plane of sharp focus to be curved.
(see aberration)
Cut film
Large format film available in flat sheets. The most common are
in "Imperial sizes": 4 ins x 5 ins and 8 ins x 10 ins
.
(see Large format)
CMYK
A colour system based on the four colours used in colour printing: Cyan, Magenta, Yellow and BlacK.
Can also be a colour mode used to define colours in a digital
image. All Digital cameras & scanners are RGB devices,
a colour method based on combinations of the primary colours Red, Green & Blue this is the same as
your TV and PC monitor. CMYK is primarily used when preparing
digital images that will be printed using the process colours
by a printer or publisher on a four colour printing press.
(see RGB)
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