Digital Camera Related Glossary Defines Digital Photography Terms

Acquire: The opening up and importing of images into an image editing program like Adobe Photoshop. The term is applied differently with in different types of software. With imaging software it is most often done through a twain interface or plug-in mini-application.

Artifact(ing): Misinterpreted information from a JPEG or compressed image. Color faults or line faults that visibly impact the image negatively.

ASCII: American Standard Code for Information Interchange (ASCII) is an ANSI binary-coding scheme consisting of 128 seven-bit patterns for printable characters and control of equipment functions. ASCII is the basis for information exchange between many computer systems.

Bit: The smallest unit of memory; a contraction from ´binary´ and ´digit´. Binary digits are 0 and 1, also known as ons and offs.

Bit Depth: This refers to the color or gray scale of an individual pixel. A pixel with 8 bits per color gives a 24 bit image. (8 Bits X 3 colors is 24 bits.) CCD are colored in a pixel by pixel method.
30/32 bit color is billions of colors. (Only supported with high-end CPU´s.)
24 bit color resolution is 16.7 million colors.
16 bit color is 32,000 colors. (this is the Macintosh Standard)
8 bit color is 256 color. (this is the Windows Standard)
8 bit gray scale is 256 shades of gray
4 bit 64 colors or gray
2 bit black or white.

Bitmap: The method of storing information that maps an image pixel, bit by bit. There are many bitmapped file formats, .bmp, .pcx, .pict, .pict-2, tiff, .tif, .gif (89a), and so on. Most image files are bit mapped. This type of file gives you the ´jaggies´, when examined closely you can see the line of pixels that create edges. Bitmap images are used by all computers. The desktop or screen information for all Windows machines uses .bmp files, while the Macintosh uses pict files.

Byte: A group of 8 bits; the basic unit of information

CCD: Charged Coupled Device, a light sensitive chip used for image gathering. In their normal condition these are greyscale devices. To create color a color pattern is laid down on the sensor pixels, using RGBG color mask. (Red, Green, Blue, and Green) The extra Green is used to create contrast in the image. The CCD Pixels gather the color from the light and pass it to the shift register for storage. * CCD are analog sensors, the digitizing happens when the electrons are passed through the A to D converter. The A to D converter converts the analog signal to a digital file or signal. The CCD is the heart of today's digital cameras.

CCITT Group III: Data compressed in one dimension yielding an average data reduction of about 5:1 or 6:1. The most common implementation of CCITT Group III is the data reduction circuit found in FAX machines. This technique is also known as "run length encoded."

CCITT Group IV: Compression in two dimensions yielding an average data reduction of 25:1 or better. CCITT Group IV compression requires the execution of 80-million bit oriented operations. The resulting compressed file is roughly the same size as a vector file consisting of graphics.

CMYK: Cyan, Magenta, Yellow, Black; These are the printer colors used to create color prints. Most Color Printers, Ink-Jet, Laser, Dye-Sublimation, Thermal, and Crayon printers use these as their printer colors. (This is one of the color management problems for computers. Converting RGB files to CMYK files cause´s color shifts.) When used by a printer the CMYK is also known as a reflective color since it is printed on paper, or reflective films. Digital cameras generally use RGB color.

Compression: Process of compacting digital data, images and text. Software algorithms search the raster image to build a greatly condensed (from a file storage perspective) format of the image. In the case of CCITT Group IV, the file size reduction is about 25:1. The actual compression factor is greatly dependent upon the quality of the scan and upon the density of the information. JPEG is the standard compression format for digital cameras.

Decompression: Process of returning a compressed file to its full bitmap.

DPI: Printing term that describes the number of dots per inch that are used to create an image. (The image can be a font or graphic). This is the same as pixals per inch.

EPS: Encapsulated Postscript, a computer file standard set by Adobe for printers, which is the mathematical definition of shapes, lines, color and space. This is one of the most accurate ways to define a font or image, but creates much larger file size. EPS files also add page description information to the files. Used on all computer, but not all postscript files are the same, nor readable between programs. EPSF is an IBM file generally, EPSP is usually found on Macintosh, and there are many different variations of each type.

Export: The act of sending a file out through a specialized mini-application, to print, compress, or to a specialized file format. With digital cameras the process of copying the digital photos from the digital camera to the computer is exporting the digital photo files from the camera to the computer.

File Format: The specific organization of data within a file. There are multiple raster and vector file formats, including TIFF, IOCA, Tiled TIFF, IGES and DXF. Some file formats have been specified for file interchange to facilitate data storage. Digital cameras use JPEG format for compressed digital photographs and TIFF format for uncompressed digital photographs.

Filter: A specialized mini-application to extend or offer unique expansions of a software package. Usually through the use of plug-in architecture. This is a key component of many imaging software packages. For example Adobe Photoshop provides many filters which can be used to touch up and manipulate images from digital cameras. Also there are many third-party plug-in filters for Adobe Photoshop.

Firmware: An Often-used microprogram or instruction set stored in ROM. Usually refers to the ROM-based software that controls an unit. Firmware is found in all computer based products from Cameras to Digital Peripherals. Digital cameras have their own operating system and that is stored, generally in flash memory, within the digital camera. From time to time digital camera manufactures will issue updates to the firmware for their digital cameras. These firmware updates may be to correct problems discovered in the camera's operating system or to add new features.

GIF: Graphic Interface designed by CompuServe for using images on line. This is a 256 color or 8 bit image. The GIF format for storing images is not generally used with today's digital cameras. The standard format for saving compressed images to memory cards by digital cameras is JPEG and for uncompressed images use the TIFF image file format.

GIF 89: The most recent GIF standard that allow the selection of area for transparency, primary use is on the internet and other on-line services. Like GIF it is 256 color or 8 bit imaging. The GIF format for storing images is not generally used with today's digital cameras. The standard format for saving compressed images to memory cards by digital cameras is JPEG and for uncompressed images use the TIFF image file format.

GUI: Pronounced Gooey, stands for graphic user interface. Refers to the computer interface with software in a user friendly appearance.

Image: Electronic representation of a document, stored and displayed as a bitmap. Various compression techniquest are in use to minimize file size and network load. In the case of digital cameras, "image" refers to the digital photographs which are captured and stored on the memory card within the digital camera.

Imaging: Term commonly used to describe both the products and industry dealing with images.

Index Color: Reduced Color mapping, 8 bit or less. Done to reduce images to their smallest size. This is only relevant in GIF images and the GIF format for storing images is not generally used with today's digital cameras. The standard format for saving compressed images to memory cards by digital cameras is JPEG and for uncompressed images use the TIFF image file format.

"Jaggies": Slang term for the stair-stepped appearance of a curved or angled line in digital photographs. The smaller the pixels, and the greater their number the less apparent the "jaggies". Also known as pixelization.

JPEG: The defacto standard for image compression in digital cameras. There are several versions of JPEG, some proprietary. JPEG, also known as JFIF takes areas of 8 x 8 pixels and compresses the information to its lowest common value. This is one of the reasons you can store so many images on the memory cards in digital cameras. Decompression compressed JPEG digital images can cause "blockyness", the "jaggies", or "pixelization" in someimages. The higher the compression ratio the more the pixelization or blockyness occurs. The greater the pixel count the less pixelization may occur.

Kilobyte: 1024 bytes, written KB. used to refer to size of files, relates to amount of information in a file. 1024 kilobytes make one megabyte. Often the size of compressed digital photographs is refered to in terms of megabytes and kilobytes.

Lab Color: L*a*b* is a color model developed by the Centre Internationale d´Eclairage (CIE). These standards are internationally accepted standards for all colormetric measurements. The Lab model, like other CIE color models, defines color values mathematically, in a device independent manner. Lab color is consistent color regardless of the device producing the color.

LPI: Printing term for Lines per Inch.

Megabyte: 1024 Kilobytes, written MB used to refer to size of files or media such as digital camera memory cards. Refers to amount of information in a file, or how much information can be contained on a hard drive or memory card. 1024 kilobytes make one megabyte. Often the size of compressed digital photographs is refered to in terms of megabytes and kilobytes.

MegaPixel: 1 Million Pixel Image. Usually produced with high-end digital cameras, and Scanners. The greater the megapixel count of an image the higher the resolution of that image.

PCX: Windows Paintbrush bitmap image standard.

Pict: The native bitmapped file format for Macintosh images.

Pict 2: The native color bitmapped image format for Macintosh, up to 32 bit color.

Pixel: The pixel is the smallest part of a digital photograph. It is one colored "dot" on a digital photograph. Also used in measuring image size and resolution, i.e., 640 x 480 is the pixel resolution of most VGA Monitors. (Note pixels are square in computers and rectangular in video)

Pixelization: The stair-stepped appearance of a curved or angled line in digital photographs. The smaller the pixels, and the greater their number, the less apparent the "pixelization" of the digital photograph. Also known as the "jaggies".

Plug-In: The plug-in architecture was first popularized by Adobe Photoshop and is now the defacto standard for all major imaging programs. Unlike Twain it allows more flexibility in design so acquire, export, and specific task can be performed with in a software application. This is the preferred choice of operation in the Macintosh and ´Power User´ computers. Plug-In ideology has spread to other applications like Netscape Navigator, Macromedia Director, and so on. Not all plug-ins work with all products, specific interfaces are required for different types of software. Adobe has become the defacto standard for image editing software, and graphic illustration software.

PPI: Printing term for Pixels per Inch

RAM: Random Access Memory, the volatile memory used to temporarily store information for processing. This is the fastest type of memory for the computer, and the most expensive. There are several types of RAM.

S-RAM: Static RAM, the most expensive type of RAM found in on-bard memory units, some Printers, and in PCMCIA Type I Cards. D-RAM, Dynamic Ram, Most often seen as the expandable RAM used by the computer for memory.

Raster: A two-dimensional array of black and white cells, called pixels or picture elements, which when displayed on a screen or paper, form an image or representation of an original document.

Rasterization : The process that automatically converts vector and text into raster. This process is done on-the-fly for plotting, or can be stored as a file in raster format.

RGB: Red, Green, Blue; the color language of computers. Computers´ monitors and digital cameras use these colors to create all the colors seen on the monitor and saved in files. Green gives the color green, but is also used for contrast control. Digital cameras generally use the RGB color space.

ROM: Read Only Memory, used for primary instructions in many Computer Peripherals and CPU´s Firmware. There instructions can be upgraded from a computer

Software: Operating Instructions for specific task based applications. These instructions are carried out by the computers processors. These include all packaged for use like image editing, word processing, databases, CAD, CAM, games, and so on. Software has to be written for a specific Computer OS. Digital cameras have their own computer processor, memory and software. Generally the software is stored on flash memory in the digital camera and can be updated if the manufacturer issues a "firmware update." The firmware update will replace the software in the digital camera with a more up-to-date version.

TIFF: Tagged Image File Format (TIFF) is an industry standard raster file format, which consists of the image and header information. TIFF is also supported by most desktop publishing and paint programs. Many digital cameras can save uncompressed images in the TIFF format, however, being uncompressed, the TIFF digital photograph files are very large and will quickly fill up even large memory cards.

Twain: An acquire interface developed by a consortium of software developers as a standard for communications between scanners, imaging devices and
now digital cameras and other and the computer software. Twain allows you to import (acquire) an image into your software. This is the interface of choice on the Window´s platform. The Twain system allows images to be imported directly from a digital camera into many software programs including Adobe Photoshop.

Vector: An electronic or computer-readable image format incorporating a formulate representation of graphical line art. Vector format is used during the markup process, to keep redlines separate from images and to facilitate easy modifications. This format is also often used during the edit process.

WYSIWYG: Slang for What You See Is What You Get, refers to accurate screen images to print out. This is a primary result of Xerox Graphics interface. Pronounced "WizzyWig"