Browse All 840 Photography Terms A–Z

Checksum Verification Files, Metadata & Workflow hash Computing a mathematical fingerprint of a file and comparing it later to confirm the data has not changed.

Chroma Colour & Colour Management C* (CIELAB) The colourfulness of an area judged relative to the brightness of a similarly lit white, a perceptually defined counterpart to saturation.

Chroma Subsampling Files, Metadata & Workflow ratio A compression technique that records colour information at lower resolution than brightness information. 4:4:4, 4:2:2, 4:2:0

Chromatic Aberration Removal Post-Processing & Retouching px Processing that eliminates coloured fringing along high-contrast edges by realigning or desaturating the offending channels.

Chromatic Adaptation Colour & Colour Management The visual system's automatic adjustment to the colour of the prevailing light, which keeps familiar objects looking the same colour under different illuminants.

Chromogenic Black and White Film Film, Darkroom & Historic Processes ISO A monochrome film that forms its image from dye couplers rather than silver, and is processed in standard colour chemistry.

Chromogenic Print Printing, Display & Output A print made on light-sensitive photographic paper and developed in chemistry, whether exposed from a negative or by a digital light source.

CIE Chromaticity Diagram Colour & Colour Management CIE xy The horseshoe-shaped plot of all colours visible to human vision, on which colour space gamuts are drawn as triangles.

CIELAB Colour & Colour Management L*a*b* A device-independent colour model with one lightness axis and two opponent colour axes, designed so equal numerical steps look equally different. ΔE = √(ΔL*² + Δa*² + Δb*²)

Cinemagraph Motion, Video & Creative Techniques seconds A still image in which a small isolated area moves in a seamless loop.

Circle of Confusion Focus & Depth of Field mm The largest blur circle that still reads as a point to the viewer, and the value on which every depth-of-field calculation depends. c ≈ diagonal / 1500

Circular Polarising Filter Optics, Lenses & Filters stops (EV) A rotating filter that blocks polarised light, cutting reflections from non-metallic surfaces and deepening blue skies. Effect peak at 90° from the sun

Clamshell Lighting Lighting & Flash A beauty setup with one soft source above the face and a reflector or second source directly below, both facing the subject.

Clarity Post-Processing & Retouching % A midtone local-contrast control that adds apparent punch and definition without affecting the extreme tones.

Clipping Exposure & Metering The loss of tonal information when values are pushed past the maximum or minimum a file can encode.

Clipping Mask Post-Processing & Retouching A layer restricted so that it only affects the single layer directly beneath it, using that layer's shape as its boundary.

Clone Stamp Post-Processing & Retouching px (brush size) A retouching tool that copies pixels from one part of an image directly onto another.

Close-up Diopter Optics, Lenses & Filters diopters A magnifying filter that screws onto the front of a lens to allow closer focusing without losing light. Working distance = 1000 / diopter power (mm)

Cloud Backup Files, Metadata & Workflow TB Storing a copy of image files on remote servers accessed over the internet.

CMOS Sensor Sensors & Digital Capture A sensor type in which each photosite has its own amplifier and the charge is converted to voltage at the pixel itself.

CMYK Printing, Display & Output % The subtractive four-ink model — cyan, magenta, yellow and black — used in commercial printing.

Codec Motion, Video & Creative Techniques The compression scheme used to encode and decode video data.

Collection Files, Metadata & Workflow count A named grouping of images assembled for a purpose, independent of where the files are stored.

Colorimeter Colour & Colour Management An instrument that measures colour through three filters approximating human vision, used mainly for calibrating displays.

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