A

acquire

A digital method of capturing images on peripheral devices (such as scanners and digital cameras) and adding the images to your hard disk drive.

album

A collection of images. Albums contains shortcuts to where the images are stored on your hard disk drive.

aliasing

When smooth lines and curves in a digital image become distorted due to low resolution.

antialiasing

A software technique for reducing jagged lines and curves by using shades of gray and color to smooth out the contrast between neighboring pixels. While this technique may result in a loss of overall image clarity, it greatly reduces the appearance of jaggies.

aperture setting

The size of the opening to admit light through the lens to expose the film. The larger the setting (f/22 .vs. f/2 for example) the smaller the opening and hence less light will arrive at the film. This could be compensated by increasing the exposure which will increase the Depth of Field. 

archive

A collection of files gathered and often compressed for storage or backup purposes.

aspect ratio

The ratio of width to height of an image.

azimuth

The angle of the shadows that extend from the edges of details in an image.

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B

banding

A disruption in the graduation of colours in a digital image. Banding can also occur when printing images on a multi-pass colour printer.

bandwidth

The amount of data that can be processed by a device. For example the amount of data sent through a network interface card (NIC) in a fixed amount of time. Bandwidth is measured in Kilobits or Megabits per second (Kbps or Mbps).

batch processing

Operations performed to more than one image at a time. For example, changing the file type or compression on a group of images.

blackpoint

The blackest area of an image. You can control the intensity of the black in an image by adjusting the blackpoint.

BMP

A file format used by Microsoft Windows for example in MS Paint. The disadvantage of the format are the large file sizes involved, but this allows the original image integrity to be maintained.

brightness

The light intensity of an image. You can make an image appear brighter or darker by adjusting the brightness.

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C

cache (memory)

A high speed storage device. For example Level 1 cache within a microprocessor core which allows for rapid manipulation of the data within the processor itself without having to request the data from 'slow' main memory.

caption

A comment or description added to an image. Captions above images are called headers, while captions below are referred to as footers. Often used to label a scene, location or persons in the image.

capture

To record a still or moving image on storage media, for example tape or flash memory. Also to transfer data from one format to another by using a PC and dedicated hardware for the purpose. For example a Video capture card can capture analogue video and convert it to Digital format.

CMYK

A colour model that uses cyan, magenta, yellow, and black as its primary colors.

codec

A technology that compresses and decompresses data. A codec can be used to compress files for transport over a network, the Internet, or to decrease size for storage. The codec then expands files to their original size so that they can be played or viewed on a computer. Stands for compressor/decompressor.

colour calibration

The process of setting up your computer so that the colour output from your printer matches the colours you see on your monitor.

colour depth

The number of colours displayed on screen of stored within the image.  Common colour depths include 256 colours (8bits / pixel) for WEB images; 16.7M colours (24bit / pixel or 8bit / colour channel) used in Jpeg images and finally 48bit / pixel or 16 bits / colour) available in TIFF file format used for image manipulation in higher quality image editing programs.

compression

The process or result of converting data to a storage format that requires less space than the original data.

contrast

A measure of the differences of colour and brightness in an image.

convert

To change media or file from one format to another.

cropping

A digital method of removing unwanted areas of an image.

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D

database

An electronic filing system where a computer stores and can quickly access the data.

decode

To read (or view) a specific file format and translate it into another format.

depth of field

The amount of the image that remains in focus surrounding the subject i.e. to what distance behind & in front of the subject. Smaller depths of field may be desirable where you wish to focus & draw attention to the subject only, for example in a portrait.

dithering

Modify the appearance of colours and shades in an image by varying the size and shape of the pixels.

DPI (dots per inch)

A measurement of the resolution of a displayed image. The more dots per inch, the higher the resolution, and therefore quality of the image.

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E

elevation

The height of an imaginary light source over an image. The elevation of the light works in conjunction with azimuth to generate a three-dimensional emboss effect.

encode

To write (or save) a specific file format often converted from a different format.

encryption

A method of converting data into a secure format. You need a password or key to read an encrypted file.

EXIF (Exchangeable Image File)

A standard for storing information, primarily with images that use JPEG compression. Most digital cameras create EXIF information. EXIF information is embedded in the image file.

export

To move data from one application to another. The data is placed into a generic format or one that the other application understands.

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F

feather

To soften the edges of an image so that the image blends into the background.

file format

A standard for encoding information in a file. Each type of file has a different file format that specifies how the information is organized and is generally specific to a particular application.

filter

A tool that can add an effect to an image.

film

A strip or sheet of celluloid material covered in a photographic emulsion that can be developed to produce positive of negative images. Film can take several formats (sizes) ranging from 110 Instamatic to Medium format & larger.

filmstrip

A strip of film, typically 35mm containing 2~6 negative images after developing.

focal length

The distance from the lens to the displayed image when it is focus. Typically the larger the focal length the larger the lens magnification.

frame

A single still image in a film strip or video.

frame rate

The rate at which frames are displayed in a film or video. Frame rate is measured in frames per second (fps).

f/stop

The aperture setting that controls the amount of light entering the lens.

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G

gamma

The range of colour values a monitor, scanner, or printer can display. Adjusting this value increases or decreases the intensity of the light spectrum. A gamma corrected image simulates the adjusted display value when it is saved. Important for getting a faithful reproduction of the original image on the chosen display device.

GIF

Graphics Interchange Format. A file format used in Web pages which is particularly efficient in size for images of fewer colours or details.

grain

'Texture' on a film that is enlarged under low light conditions. The term is of chemical origin due to the exposure & development processes involved but still applicable for digital images. Larger grain sizes generally detract from the sharpness of the final image.

gray scale

An image composed of different shades of gray.

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H

hue

The predominant colour in an image.

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I

image editor

A program, such as Adobe Photoshop or ACD FotoCanvas, that can be used to create and edit images.

image optimizer

A program that you can use to make your images more suitable for the Internet.

image resolution

Refers to the quality of the details and colours in an image. It is also used to describe the quality of monitors and printer output.

image viewer

A program that displays images. For example, Nikon View.

import

To bring data into an application from another using a format that the receiving application understands.

interpolation

A process that uses nearby pixels to estimate the colour of new pixels to be added that were not in the original resolution of the imaging device.

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J

jaggies

Individual pixels displayed in an image with low resolution. The appearance of pixels in an image cause lines and curves to look jagged. Typically observed where the original image compression is set too high or the image is zoom in to the extreme.

JPEG

Commonly used compression format proposed by the Joint Photographic Experts Group. Offers 24 bit support an excellent compression vs. quality characteristics.

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K

KDC

Kodak Digital Camera format.

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L

lossless compression (encoding)

A form of encoding where no data is lost, and therefore image quality is maintained with a small reduction in original file size.

lossless rotation

The rotation of a JPEG image without the loss of image quality.

lossy compression

A form of compression that attempts to discard unnecessary data. This data loss can affect the quality of the image but greatly reduces the file size.

luminance

The brightness, darkness, and contrast information of an image.

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M

metadata

Information about an image. For example, metadata with images from digital cameras can contain the date and time the picture was taken, the shutter speed, the exposure settings of the camera, and if a flash was used.

monochrome

An image containing a single colour.

multiple page image

An image that contains more than one image in a single file. For example, images that use the .tif file extension can have multiple pages.

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N

negative

One frame from a developed film. For example 35mm negatives are part of the original roll of 35mm file which have been cut into strips (4~6 images typically) after processing.

noise

The random errors generated by your imaging device in less than optimal conditions. For example in low light conditions on cameras.

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O

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P

photo album

See "album".

photo editor

See "image editor".

picture viewer

See "image viewer".

pixel (PICture ELement)

The smallest piece of a digital image, arranged in rows and columns.

PNG

Portable Networks Graphics format. Combines the best qualities of GIF & JPEG formats offering higher compatibility than previous compression formats.

PPI (pixels per inch)

One dot on your image display device is one pixel. Hence pixels per inch are a measurement of image resolution. The greater the number of pixels per inch, the higher the quality of the image.

primary colours

Colors that can produce other colours by mixing them together. For example, in the RGB colour model, red, green, and blue are primary colours.

progressive

A JPEG image display mechanism whereby the image quality builds up until the final image is displayed in its full resolution.  Used for web pages when downloads speeds can be a factor.

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Q

QTIF

Quick Time Format.

QuickTime

A video and animation system developed by Apple Computer and built into the Macintosh operating system and iTunes.

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R

raster image

An image composed of a rectangular grid of pixels. Each pixel contains a defined value about its colour, size, and location in the image. Therefore, resizing the image can affect its quality.

render

To draw images to your display device.

resolution

The quality and clarity of an image, measured in pixels, dots per inch, or pixels per inch.

RGB

A colour model that uses red, green, and blue as its primary colours.

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S

sample

An audio wave, measured in bits. The more bits in a sample, the better the clarity and fidelity.

sample rate

The number of samples used per second to digitally represent a sound, measured in Hertz (Hz - cycles per second). The more samples taken per second, the more accurate the digital representation of the sound. The sample rate of an audio recording is one of the factors that determines the overall sound quality.

sample size

The size of each sample, measured in bits.

scale

When printing an image, scaling can reduce or enlarge the image to the desired final result.

saturation

Saturation refers to the intensity of a specific hue. A highly saturated hue has a vivid, intense colour, while a less saturated hue appears more muted and grey. With no saturation at all, the hue becomes a shade of grey.

slide

A single frame of a transparency (commonly 35mm) that has been mounted in a cardboard or plastic mount for mechanical robustness & display purposes.

slide show

An automated sequential display of images.

streaming

Playing an audio or video file as it downloads from the Internet.

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T

thumbnails

A small preview of a full-sized image.

TIFF

Tagged Image File Format. TIFF is a popular format for high colour depth images and is widely supported by image-manipulation applications such as Photoshop.

timestamp

The dates and times associated with a file.

transparency

A single image or frame of a film that has been developed to show a positive image of the original subject.

TWAIN

Interface standard for scanners and certain digital cameras.

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U

USB (Universal Serial Bus)

A computer port for connecting peripheral devices, such as mouse devices, keyboards, cameras, and scanners.

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V

vector image

An image made up of individual objects instead of pixels. The objects are defined by mathematical equations. You can adjust the size of a vector image and the image remains clear and of high quality.

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W

watermark

A small semi-transparent graphic added to an image, usually to provide copyright protection.

whitepoint

The whitest area of an image. You can control the intensity of the white in an image by adjusting the whitepoint.

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X

XML (Extensible Markup Language)

A standard language for documents on the Web.

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Y

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Z

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