Photography Glossary

Yogesh Sarkar

Active-Matrix Display: A type of flat panel LCD display used in laptop and portable computers. Active matrix displays produce a superior image to passive matrix displays.

Additive Colors:
The three additive primary colors are red, green and blue. When these three colors of light are mixed in equal proportions they will produce white light. Also known as additive primaries.

Advanced Photo System: Sometimes referred to as APS. The new imaging system centered around a new film cartridge, with cameras, film, and photo finishing all talking to one another to avoid errors, produce pictures of the best quality, and organize these pictures for easy retrieval.

Advanced Photo System Cassette: The film cartridge loaded into the camera and then used to store the processed negatives. It has indicators to show if the film a) is new b) has been used (exposed) partly c) has been used (exposed) completely d) has been processed. If the Film has been completely used or processed, the cassette cannot be put back into the camera.

Advantix: Eastman Kodak's brand name for their APS products.

Airbrushing: A software tool found in many image editing programs that simulates the effect of a mechanical airbrush.

Aliasing: The visual stair-stepping of edges that occurs in an image when the resolution is too low. This can be caused by improper image sampling or improper image processing.

Anti-Aliasing: A technique used to smooth the transition between adjacent image areas. The removal or softening of jagged (aliased) edges by averaging or blending techniques.

This is the opening in the lens that controls how much light goes through to the film. Apertures are marked in f/stops. The smaller the number, the larger the aperture.

Archive: Storage of selected digital files for backup or long-term storage.

Artifact: Unwanted visual anomalies or defects generated by an input or output device, or by a software operation, that degrade image quality.

Artificial Intelligence: The use of computers to solve problems and process information in ways that approximate human thought.

Aspect Ratio: The relationship of an image's horizontal length and vertical height. The horizontal length number is placed first (i.e. 3:2).

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Backprinting: Up to two lines of information, like exposure data, time, date, location can be printed on the back of each picture. This information can be recorded in the camera or later be put on with special equipment.

Barrel Distortion: Image distortion that spreads the center dimensions of the picture.

Base Resolution:
The Photo CD image resolution (512 x 768 pixels) that is formatted for display on current consumer televisions.

4 Base: The 1536 x 1024 pixel image that is scanned and stored on a Photo CD. This image is ready to be used by High Definition Television Systems.

16 Base: The 2048 x 3072 pixels image that is scanned and stored on a Photo CD and suitable for digital imaging and desktop publishing applications.

64 Base: The maximum resolution image file that is available on Pro Photo CD disks. This 4000 x 6000 pixel file produces a 72 megabyte color image.

Baud Rate: Used interchangeably with "Bits Per Second." The unit of measure used to rate the speed at which computer data can be translated via modem. Typical modem rates are 2,400, 9,600, 14,400, and 28,000 baud.

Bitmap Graphics:
Graphics that are constructed of individual pixels.
Bitmapped images: Images made out of an array of dots. Each dot is represented by either a single number or a set of three or even four numbers ranging from 0 to 255. Photo CD and Photo Floppy images are bitmap images.

Black: The fourth color in four-color printing. It is listed as the K in "CMYK." Black is required in the printing process because equal amounts of cyan, magenta and yellow inks will not produce a true black.

Bleed: Printing term referring to an image or inked area which extends to the edge of a printed piece. The bleed is the portion of the artwork that is beyond the trim marks of the piece. The bleed is required to account for any slight misalignment during trimming which would otherwise result in an unprinted strip of paper appearing at the edge of the finished piece.

Blend: In computer graphics software, the intermediate steps between two objects that are created when the objects are merged together via a specified number of intermediate transformations.

BPI (Bits Per Inch): A term defining the density of data in a bitmap image.

BPS (Bits Per Second): A measurement of the speed of data transfer, used interchangeably with the term baud per second. In many image editing programs, this is the term describing a special effects filter that performs a specific function, such smoothing selective edges. In some cases, the image editing programs present the brushes as an icon that actually looks like a brush.

Bubble Jet: A Canon ink jet printing technology that creates bubbles in the ink supply and propels the ink through small nozzles onto the print media.

Part of the computer's memory used for temporary storage of information. This becomes necessary to compensate for differences in speed that different devices can transmit or receive data.

Bus: A data pathway used within a computer system to transfer information within the system.

A bundle of data containing eight bits. This is the common size unit for computer data.

C format: A 4x6 print. The Classic print format, best for close-ups of people.

Camcorder: Video camera and video recorder in one unit. Very portable, compact and convenient.

Calibration: A process of setting digital imaging components to standardized settings that will produce accurate and predictable results in the output.

Capture: Acquiring information, such as an image, with a scanner or digital camera device.

CCD Array: An arrangement of CCD sensors mounted in close proximity that allows for the simultaneous capturing of many pixels with one exposure.

CD-ROM (CD-Read-Only Memory): A compact disc format that allows storage of information in a read only format.

CD-R (CD-Recordable): A CD format that allows the users to record data to a disc when using the proper hardware. Recorded data is not erasable.

CD-ROM-XA (CD-ROM Extended Architecture): A specific type of compact disc-read only device that is compatible with the Photo CD format and other CD applications. Multiple session Photo CD's cannot be fully utilized on non-XA drives.

Chroma: The hue or color information associated with an image.
Chrominance: The portions of a signal that are dedicated to describing the hue and saturation. Used in measuring the difference between two colors of equal brightness.

CMY (Cyan, Magenta, Yellow): These three subtractive primary colors are used in color-negative printing and in some color output devices to produce a full gamut of color. The combination of pure CMY inks produces black, and the elimination of all three produces white.

CMYK (Cyan, Magenta, Yellow and Black): The four colors of ink that are used in "four color process" printing to create the appearance of a photographic or full color. Black is added to compensate for the lack of purity in CMY inks.

Color Calibration: A system of software and/or hardware that matches the colors between two or more digital devices. Color calibration systems commonly compare device color profiles and translate one color model into a device-independent language that the next color device can use.
Color Correction: The process of adjusting an image to compensate for scanner deficiencies or output device characteristics.

Color Curve: A graphic mechanism for displaying color measurements and for making color changes to an image. User adjustments to the angle and slope of the curve implement color changes to one or all of an images color channels.

Color Key: A printer's proofing system developed by 3M that makes separate acetate sheets of CMYK that when stacked give a representation of the offset printing of a color image.

Color Management System (CMS): A combination of software and or hardware devices used to produce accurate color results throughout a digital imaging system.

Color Model: Refers to the component colors used in the image, such as RGB or CMYK. This is also called a Color Space or Color System.
Color Separation: The electronic or photographic process of separating a single RGB color image into the three subtractive primary colors CMY plus K (black) that will be used for reproduction. These four monochrome films are used to produce the plates in four color printing.

Color Temperature: A scale used to refer to the visible energy system of various light sources. The scale uses degrees Kelvin as a measure of the mixture on a scale from red to blue white. Daylight = 5500 Kelvin, a blue-white color. The Tungsten in a light bulb produces about 3200 Kelvin, an orange color.

Colorimeter: A device for measuring color values.

Composite Video: A video signal that includes the luminance and chrominance signals, along with the burst signal and sync signals. Composite video signals are transmitted over a single wire. The standard television signal.

Compression: The process of reducing the size of a data file, usually accomplished through software processing. This is used to reduce the required storage space or cut transmission times.

Computer Program: Term used to describe a specific piece of software for a computer system. Sometimes referred to as an application.

Computer-to-Plate: A method of applying an image onto an offset printing plate. The image is transferred from a computer directly to the device that exposes the image onto the plate, bypassing the need for separations and film.

Console: Terminology sometimes used to describe a computer monitor and keyboard. Contact Print: A photographic print made from a negative or positive original in contact with a photographically sensitive film, paper, or printing plate.

Contrast: The measure of difference between the lightest and darkest values appearing in an image. High-contrast images contain mainly dark values and white values with few steps or tones available in the image.

Cyan: One of the three subtractive primary colors. Produced by mixing equal amounts of blue and green projected light. Cyan is also one of the four colors used in 4-color printing.

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Digital Image: A picture that is in computer language. Because the picture is represented by a series of numbers, it is very easy and improve the image or to alter it.

Digital: A computer's rendition of an image. These digital images can be retouched and enhanced and then printed.

D-RAM (Dynamic Random Access Memory): The term describes memory within the computer that is constantly changing.

DAT (Digital Audio Tape): A recording format that is commonly used for data storage and data backup because of its low cost per megabyte.

Data: The numbers that make up a digital file.

Data Compression: The process of reducing the size of a data file, usually accomplished through software processing.

Densitometer: A device used to measure the density of light transmitted or reflected by paper or film. It is used to check the accuracy, quality and consistency of an output device.

Density: The degree of opacity of a photographic film.

Descreening: A feature of some scanners that allow them to eliminate moir? patterns that can occur.

Digit: A single unit from which all data is built.

Digital: Information or data that exists as numerical values (1 or 0) based on a binary coding system.

Digital Camera: A filmless camera system. Any camera system that is capable of converting an analog image info a digital signal or file.

Digital Printer: Any printing device that is capable of translating digital data into hardcopy output.

Digitize: The process of sampling analog data and converting (quantizing) the signal into a digital data format usable by a computer.

Direct Memory Access: The ability to use memory without a software interface.

Direct-to-Press Printing: Printing devices that allow for the elimination of film separations from the printing process. These systems utilize a computer controlled system employing lasers to "write" digital data to a plate that is already mounted on the press.

Disc: The spelling variation of "disk" referring to compact discs such as Photo CD or other CD-ROM.

Dithering: A process used by some output devices to simulate shades of gray or color variations with a randomizing technique that uses varying sizes and shapes of pixel groupings instead of an ordered array of halftone dotes.

Dot: Dots make up an image in color separations or halftones. Halftone dots will have a fixed density but have variable size (amplitude modulation).

Dot Gain: The effect produced by the expansion of individual dots in a halftone screen when printed onto paper. Dot gain results in a darkening of a printed image and is influenced by the tendency of different papers to absorb ink.

Dot Matrix: An impact printing process that uses a series of dots to create all images, lines and text.

Dot Pitch: The distance between the dots on a computer monitor, typically 0.2 to 0.3 millimeters. The closer the dots the sharper the image on the monitor.

DPI (Dots Per Inch): The unit of measure used to describe the resolution of image files, scanners, or output devices. The measure of distinct pixels that a device can produce either horizontally or vertically in one inch.

Dye Sublimation (Diffusion Transfer): A color printing technology that forms the image by delivering gaseous dyes to the receiver material with a thermal driver. This creates near photographic quality images.

Emulsion Side: The side of photographic film or paper coated with the silver emulsion. Film output is specified as emulsion up, or emulsion down.

Encapsulated PostScript (EPS): A file format developed by Adobe that stores graphics and text as Postscript language commands that a printer can read and print. These files contain low resolution preview files in addition to the high resolution Postscript commands.

Endeavor: Fuji's brand name for their APS products.

Error Diffusion: A screening technology used in digital continuous tone printers where fixed-sized dots are placed based on image detail and tone values to enhance sharpness and detail while avoiding posterization problems.

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FSI: Film Status Indicators, the icons on the end of the cassette indicating whether the film is unexposed, partially exposed, fully exposed but not processed, processed.

Feathering: A technique in many image editing programs that allows for the softening of the edge around a selection.

File Format: The particular arrangement of digital information that is saved from an application program. The method of arrangement or storage is unique for any particular application program, but most applications can import and export standardized graphic and text file formats, such as TIFF, GIF, and EPS graphics; or RTF or ASCII text.

Film Speed: The relative index, also called ISO, of how much light a film requires to be properly exposed. A 100 ISO film requires four times the light of a 400 ISO (speed) film for correct exposure. Rule of thumb: Dull day-high speed, bright day-low speed

Filters: Software that is used to modify digital images by altering the values or arrangement of selected image pixels.

FlashPix: An image file format developed and supported by Eastman Kodak Co., Microsoft Corp., Hewlett-Packard, Live Picture and other companies. The format uses FITS see FITS) technology to facilitate the transmission and manipulation of large image files.

Flatbed Scanner: A scanner which utilizes CCD linear arrays, where the image is placed on a glass platen, and the CCD array moves past the artwork.

Flying Erase Head: A type of recording head on a VCR or camcorder whereby there is no static when stopping and starting between scenes.

Focal Length: A lens measurement (in millimeters) that determines how big an image will be. It's the focal length which determines the perspective, i.e., wide angle through telephoto.

Ghosting: The effect of changing an object's level of opacity

GIF (Graphics Interchange Format): A graphics file format common to online services and the Internet. A GIF utilizes a Ito 8-bit palette to minimize file size (pronounced "jiff").

Gigabyte (GB): Approximately one billion bytes (1000 Megabytes). The exact number is 1,073,741,824 bytes.

Gray Scale (or Grayscale): An image containing a range of gray levels as opposed to only pure black and pure white.

Green: One of the three additive primary colors of light (Red, Green and Blue)

H format: A 4x7 print. Similar to the motion picture and HDTV screen format.

Halftone: The process of reproducing a continuous tone image as a series of various sized dots within a fixed grid that can be reproduced with ink on a printing press. The finer the dot grid the higher the quality of the reproduction.

HDTV (High-Definition Television): A television system that incorporates 1000 or more horizontal lines of resolution (twice current standards) along with a wider aspect ratio and digital quality audio.

Hertz (Hz.): A scale used for measuring the number of cycles per second.

Hi-Fi Color: An alternative printing process that extends the capabilities of printing presses. This system uses stochastic screening, 6-color printing, and other techniques to expand the possible color gamut well beyond that of traditional 4-color processes.

Highlight: The brightest/lightest area within an image.

Horizontal Resolution: The number of vertical lines that a system is capable of producing (counted on a horizontal axis).

HSB (Hue, Saturation, and Brightness): A color model that utilizes Hue, Saturation, and Brightness as the three coordinates.

HSV (Hue, Saturation, and Value): A color model that utilizes Hue, Saturation, and Value as the three coordinates.

Hue: One of the components of color. The hue can be specified by the particular wavelengths or by CIE coordinates.

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IHS (Intensity, Hue, and Saturation): A color model where colors are expressed by three values representing Intensity, Hue, and Saturation.

Ink Jet: A nonimpact printing technology where ink droplets are propelled at the paper to form characters or graphics.

IPI: Irreversible Processed Indicator, a tab on the cassette. Depressed or broken in photofinishing to serve as an alternative indicator that the cassette has been processed.

IX [Information Exchange]: This is the designation for how the camera, film and photofinishing equipment communicate with each other. There are two types of Information Exchange. Optical Information Exchange simply exposes marks on the film in a reserved area. This is used to tell the photofinisher what format of picture you selected (C, H, or P) when the photo was taken. Magnetic Information Exchange has even more information. It can tell the photofinisher about the conditions that the picture was taken so that it can be printed to its best. It can also record greetings and information (date, time, name of event, etc.) which can be printed on the back (see Backprinting).

Index Print: A 4x7 print with small images of the pictures on your roll of film. the index print makes for easy identification to match pictures to negatives.

JPEG (Joint Photographic Experts Group): A graphics file format designed for use with photographs and other color bitmaps. The JPEG format uses compression algorithms and an "averaging" technique to create files that are smaller than would be the case with other graphics file formats. Saving an image as a JPEG files does cause a very minor loss of image data and in some cases, quality.

K (Kilobyte): 1,024 bytes of computer memory.

Kelvin: A temperature measuring scale used to describe the color of light. The lower the color temperature the redder the light, and the higher the color temperature the bluer the light.

Kerning: The fine adjustment of the spacing between pairs of type characters in a word to create visually pleasing and consistent spacing.

Landscape, Landscape Mode: The orientation of an image that is wider than it is tall; a setting controlling an output device to properly fit a computer document to the print medium.

Leaderless Thrusting: A unique capability of APS cassette which enables the active light lock door to be opened and the film strip to be thrust into the camera body for loading.

Lightness: A concept often referred to as brightness that refers to the amount of perceived light reflecting or emanating from a subject; also refereed to as Luminance.

Line Art: Artwork that is only black and white, with no other tones included.

Line Screen: A term referring to the organization of elements of a halftone printing screen. Normally used to define the density of the screen; i.e. a 133 Line Screen refers to a pattern with 133 halftone dots/inch. A higher or "finer" line screen will create a sharper, more detailed image.

LPI (Lines Per Inch): See "Line Screen"

Luminance: The lightness or brightness of an image. A concept and control in some software that changes or imports only the color lightness information within an image.

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Macro: A term used to identify a photograph which is taken at a very close distance to the subject. Normally so close the image size on the negative is 1-to-1 or larger.

Macro: A predetermined pattern of key strokes that are activated to save time when doing a repetitive task on the computer.

Magenta: A subtractive primary color for printing. It is made up of equal parts of red and blue projected light.

Megabyte (MB): 1,048,576 million bytes of computer memory.

MHz (Megahertz): A unit of measure for frequency that relates to the processing speed of a computer. Equal to one million hertz.

Moir? Pattern: A visual defect that occurs in half-tone printing when the dots of the different separations used to create the half-tone image are at the wrong angles (See Screen Angles).

MPEG (Motion Pictures Expert Group): A motion picture compression system.

Negative: Film containing a reversal of an image, such that the values of the original are reversed with light becoming dark, and vice versa.

Newton Rings: Concentric multicolored rings caused by the pressing of film to glass. This can be a problem in scanning from negatives or transparencies.

Noise: In image editing applications, a random pattern of unwanted pixels or pixel groupings called artifacts.

Normal Lens: This category has a focal length of 50mm for 35mm cameras.

Nuvis: Nikon's brand name for their APS products.

OCR (Optical Character Recognition): Software that allows the computer to convert documents that have been scanned and saved in a graphics format back into editable text.

Offset Printing (Offset Lithography): A common printing process that makes prints by transferring ink to a rotating "blanket" that contacts the paper.

P format: A 4x10 print. The panoramic format, perfect for wide shots.

PAL (Phase Alternation Line): A standard for video that is common in Western Europe, Australia and other countries.

Palette: The range of color or tone available in the imaging process, or a movable menu of tools or options found in software applications.

Panoramic: A camera format which crops the top and bottom of the negative resulting in a long skinny photograph, with an illusion of vista.

Pantone: A company producing numerous color matching systems for print and computer applications. The PMS color matching system is commonly used to represent 3000 distinct colors through a numbering system.

Pantone Matching System (PMS): A printing industry-standard set of color inks.

Pixel: A term common in computer imaging referring to a picture element.

Point: A unit of measurement used in the graphic arts industry. There are 12 points to a Pica. One point equals approximately 1/72 inch. See "Postscript Point."

Point & Shoot cameras: With these cameras you are looking through a separate window (viewfinder) instead of through the lens. These cameras are less expensive, smaller and easier to carry. The disadvantages are under-powered flash, increased red-eye problems and limited flexibility to add other lenses, flashes, etc.

Portrait, Portrait Mode: The orientation of an image that is taller than it is wide; a setting controlling an output device to properly fit a computer document to the print medium.

PPI (Pixels Per Inch): Often used interchangeably with DPI, PPI refers to the number of pixels per inch in an image.

Primary Color: A color that is the basis for all other color combinations. The primary colors are Red, Green and Blue (RGB) in light; Cyan, Magenta and Yellow (CMY) in color photographic printing. In offset color printing, black (K) is added to CMY inks to more accurately reproduce an image.

Process Color: The colors Cyan, Magenta, Yellow, plus Black, used for offset printing.

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RAM (Random Access Memory): The high-speed portion of the computer's memory that is held on special chips for use in current applications or procedures.

Raster Image: An image that is defined as a collection of pixels arranged in a rectangular array See "Bitmap."

Rasterization: Changing vector type image information to raster image information.

Red: An additive primary color.

Reflective: Refers to print material that is viewed with the light on the same side of the image as the viewer.

Rendering: Applying shading and lighting effects to a two dimensional image to create the look of a three dimensional object.

Resolution: A measure of how closely packed the dots in a bitmapped image are, often expressed in dots per inch (dpi) or lines per inch (lpi). The higher the number, the higher the quality. However, doubling the resolution of an image results in a computer file four times as large, requiring more hard disk space and computer memory to handle the higher quality image. Resolution is also used to describe how close together a computer printer can print dots in an image. Again, the larger the number, the higher the quality. It is important to know the capability of the printer's resolution before scanning an image in order to get enough information to print the best quality.

Resolution: The particular pixel density of an image, or the number of dots per inch a device is capable of recognizing or producing. See "DPI" and "PPI."

Retouching: Removing imperfections or unwanted portions of an image.

RGB: A color model using red, green, and blue; the additive primary colors. Video display systems use RGB data to create screen images.

RIP (Raster Image Processor): A processor used to convert information from a graphics application into raster data for output on a printer.

ROM (Read-Only Memory): A memory type that cannot be changed or rewritten, and will not lose information when a computer is shut down.

Saturation: The amount of chroma present in a color. Pastels are low saturation while bright colors are said to be highly saturated.

Scan: The process of translating a picture from artwork or transparency into digital information. Screen Angles. In half-tone printing, these are the angles at which halftone screens are placed to avoid moire patterns on the final image. The most commonly used angles are: Black = 45 degrees; Magenta = 75 degrees; Yellow = 90 degrees; Cyan = 105 degrees.

Screening: The process of using screens or digital methods to create halftone screen representations of continuous tone images.

SCSI Port: The connection used by SCSI devices to connect to the CPU. Often SCSI devices are used in a series called a "Scuzzie Chain."

Shade: The brightness or luminance of an image when compared to a gray scale.

Shadow: Detail or information contained in dark areas of an image.

Shadow Point: The darkest tone printable in an image without being black. All tonal values below this threshold will print as black.

Shadowing: The process of copying ROM information into RAM.

Sharpening: A picture enhancement making the image have more distinct borders, areas, lines or tones.

Silhouetting: A masking or image blocking that isolates and image from the background.

Slide: A mounted 35mm transparency designed for projection.

SLR cameras: When you look into the viewfinder in these cameras you are actually looking through the camera lens. They are highly flexible. You can change lenses as you choose as well as most other accessories for creative picture-taking.

SmartFilm: Fuji's brand name for their APS products.

Smooth: A process that softens, blurs or makes an image, color or pattern to appear out of focus.

Spectrophotometer: Device used to measure the quality and accuracy of a color monitor and the film or paper output.

Spot Color: A single color ink used independently in a printed piece, as opposed to a process color which is used in overlapping combinations of other process inks to create any of a large spectrum of colors.

Subtractive Primaries: These are the three colors that are used to create all other colors in color photographic printing. (Cyan, Magenta and Yellow)

Superimpose: To place one element over another to create stacking of images or overlays.

Telephoto Lens: This category has a focal length that is greater than 50mm for 35mm cameras and makes the subject seem closer.

Thermal Transfer: A technology that uses heat to deposit dye on a receiver material.

32 Bit Color: A digital image format that incorporates 256 shades in 8-bits for each of three color channels (RGB) and includes a mask (alpha) channel with a possible 256 levels of opacity.

Thumbnail: A small low resolution version of an image.

TIFF (Tagged Image File Format): A common bitmap image format developed by Aldus. TIFFs can be black-and-white, grayscale or color.

Tint: Some percentage of a solid ink. Tints are created by using a screen to create the impression of a lighter color when the ink is printed onto paper or another medium.

Tungsten: Metal in filament of bulbs creating illumination when electronically charged. Tungsten= 3200 Kelvin an orange color.

24-bit Color: A digital color model that uses eight bits each for the three additive colors red, green and blue; creating more than 16 million colors.

Unsharp Masking (USM): The sharpening of an image by creating contrast at contrasting edges of the element.

UnZip: To decompress a file (usually text) using PKUNZIP or WinZip, two popular programs. The decompression takes place automatically when a Zip compressed file is opened (See Zip).

Vectis: Minolta's brand name for their APS products.

Vector Image: A computer image that uses mathematical descriptions of paths and fills to define the graphic, as opposed to individual pixels.

Vignette: A transition from one color or intensity to another.

White: The result of combining the additive primary colors (Red, Green and Blue).

White Point: The lightest tone printable in an image. All tone values above this threshold will print as white.

Wide Angle Lens: Lenses with a focal length that is less than 50mm for 35mm cameras and gives a wider field of view.

Yellow: A subtractive primary color for color printing and printing. It is made up of equal parts of red and green projected light.

Zip: To compress a file (usually text) using PKZIP or WinZIP, two popular programs. Commonly used to reduce the size of a file to speed up transmission over the internet or an on-line service.

Zoom: Making the image or image part become larger (zooming in) or smaller (zooming out) as it appears on the monitor.