Graphic File Formats

a glossary of formats for digital imaging students


FILE FORMAT -The specific way in which any file is saved. It is identified by the three letter extension (IBM-compatible computers) or four+ letter extension following a period (dot) at the end of the identifying file name: filename.ext. Every format has its own characteristics, advantages and disadvantages. You cannot just name change the file extension to another set of letters; it must be converted for use in different programs. Most graphic programs are able to perform the format conversion viz. you can import a graphic with one file format extension and export it/save it as another type of file format.

file extension

acronym meaning

definition

bmp

(pronounced as separate letters)

BitMaPped graphic standard, non-compressed bit-mapped graphics format used in the Windows. BMP files store graphics in a format called device-independent bitmap (DIB). Bitmap images, also called raster images, use a grid (the bitmap or raster) of small squares known as pixels to represent images. Each pixel is assigned a specific location and color value.

cgm

(pronounced as separate letters)

Computer Graphics Metafile file format designed to be a standard vector graphics file
format.
Supported by a wide variety of software, particularly word processing programs.

dib

(pronounced as dib)

Device-Independent Bitmap bit-mapped graphics format
used by Windows. When stored, the DIB format generally end with a .bmp extension & represents colors in a format independent of the final output device. When a DIB image is sent to output (to a monitor or printer), the device driver translates the DIB to colors that the device can display.

eps

(pronounced as separate letters)

Encapsulated Post Script graphics file format used by the PostScript language. EPS files can be either binary or ASCII. The term EPS usually implies that the file contains a bit-mapped representation of the graphics for display purposes. In
contrast, PostScript files, referring to fonts, include only the PostScript commands for printing the graphic.

fpx

(pronounced as separate letters)

FlashPiX format for storing digital images,
especially digital photographs,
developed by Eastman Kodak Company. It has the ability to store various resolutions of an image in a single file use of Microsoft's OLE structured storage format, which enables developers to extend the format
built-in linking support so that different applications can link to the same image in different ways. 
IMPORTANT:
Currently, FlashPix is not supported by most imaging software.

gif

(pronounced jiff or giff (hard g)

Graphics Interchange Format

standard bit-mapped graphics file format used by the World Wide Web developed by CompuServe in the late 1980s. GIF supports 256 (216-on IBM-based monitors) levels of color.

img

(pronounced image)

IMaGe graphic format handles monochrome and gray level images (originally designed to work with the GEM Paint Program). VENTURA Publisher application supports the IMG file format while various other desktop publishing applications have added support for importing and exporting this format although usually not processing it.

jpg
or jpeg

(pronounced jay-peg)

Joint Photographic Experts
Group
a lossy data compression for color images especially effective for scanned photos. There are varying levels of compression with varying loss of detail. At the highest compression (lowest quality), it can reduce files sizes to about 5% of their normal size. Lossy compression throws away some of the graphic data every time it is used to save. It does not lose data when merely opening a file, as on the Internet.

mac

(pronounced mac)

MAC paint graphic monochrome MacPaint graphic file format. In order to take a MAC file from a Macintosh to a PC, a "MacBinary" header has to be added to the file format. MAC images can be transferred "back" from a PC to a Macintosh. The MAC format always requires an image width of 576 pixels and a height of 720 lines. For that reason files converted to the MacPaint format from other formats will be cropped or padded out as necessary to fit in the 576X720 pixels size.

pcd

(pronounced as separate letters)

? Photo Compact Disc graphic file a multi-resolution compressed file format created for KodakŪ Photo CD™ files on Pro Photo CD discs. 5 levels of quality are in the format from thumbnail (lowest quality, small size files) to 18M files for high quality use. The Kodak Precision Color Management System (KPCMS) lets you control the color mode and display of Photo CD images by specifying profiles for the source film and the destination output device.
Note: You can open PCD files in one of the resolutions in Adobe Photoshop but cannot save files in the Photo CD format.

pcx

(pronounced as separate letters)

PC paintbrush piX
by ZSOFT
a graphics file format for graphics
programs running on PCs. It is supported by most optical scanners, fax programs, and desktop publishing systems.

pdd and psd

(pronounced as separate letters)

? PhotoShop Designated file native Adobe Photoshop graphic file formats that takes up less memory than uncompressed TIF files. Saves masks, layers, clipping paths, and alpha channels with the graphic. Not a recognized import file for all programs.

pdf

(pronounced as separate letters)

Portable Document Format
by Adobe Acrobat
Identical to PostScript pages, PDF files can represent both vector and bitmap graphics, and can contain electronic document search and navigation features such as electronic links. Photoshop PDF format supports RGB, indexed-color, CMYK, grayscale, Bitmap, and Lab color modes, and does not support alpha channels. The format supports JPEG and ZIP compression, except for Bitmap-mode files, which use CCITT Group 4 compression when saved as Photoshop PDF. When you open a PDF created by another application, Photoshop rasterizes the file.

pic

(pronounced as pic)

PICtor graphic file
generated and used by PICTOR, PC-Paint and GRASP.

16 color PIC files have a non-common structure in their color manifestations & will produce a temporary scratch file while packing or unpacking a 16 color PIC file. Also used for Lotus Picture File, the graphics file format used to represent graphics generated by Lotus 1-2-3. PIC file format is not compatible with the Lotus 1-2-3 PIC drawing files

pict

(pronounced as pict)

PICTure file format Mac graphic file format used for and for screen display in page-layout applications as an intermediary file format for transferring files between programs. The PICT format supports RGB files with a single alpha channel, and indexed-color, grayscale, and Bitmap files without alpha channels. It is not used for printed images since the format does not carry the information needed for separations.

png

(pronounced ping)

Portable Network Graphics a new bit-mapped graphics format similar to GIF. Approved as a standard by the WWW consortium to replace
GIF because GIF uses a patented data
compression algorithm called LZW. In
contrast, PNG is completely patent- and
license-free. Only the most recent versions of Netscape Navigator and Microsoft Internet Explorer now support PNG.

raw

(pronounced as raw)

RAW graphic a flexible basic file format for transferring files between applications and computer platforms. This format consists of a stream of bytes describing the color information in the file. Each pixel is described in binary format, with 0 equaling black and 255 white (for images with 16-bit channels, the white value is 65535). You can specify the file extension (Windows), file type (Mac OS), file creator (MacOS), and header information. It supports CMYK, RGB, and grayscale files with alpha channels, and multichannel, Lab, indexed-color, and duotone files without alpha channels.

tif
or tiff

(pronounced as tif)

 

Tagged Image File Format one of the most widely supported lossless (does not lose information during compression) file formats for storing bit-mapped images (both PCs and Macintosh computers). TIFF graphics can be any resolution, in black and white, gray-scaled, or color.  Is used un-compressed or LZW compressed.

tga

(pronounced targa)

TarGA format
developed by Truevision for their Targa and Vista products.
an industry standard designed for high-end paint programs and ray tracing packages on systems that use MS-DOS color applications. It is not as widely supported as PCX or TIFF formats nor in Windows-only applications. It was one of the first formats able to handle images with up to sixteen million unique colors. TGA files may be saved compressed (run length encoded) or not compressed.

wpg

(pronounced as separate letters)

WordPerfect Graphic file format that can contain bitmaps, line art, and vector graphics. When using an application other than WordPerfect for viewing a WPG file containing both bitmapped and vector elements, the vector elements will be discarded. This is why they may look poor in other programs.

wmf

(pronounced as separate letters)

Windows Metafile Format

graphics file format used to exchange
graphics information between Microsoft
Windows applications. WMF files can
hold both vector and bit-mapped images.

I have tried to list as many of the most common graphic file formats that are platform-independent (unless otherwise noted), which means you can use them on a PC, Mac or UNIX machine as long as you have a program that can use them.

For video, the popular extensions are .AVI for the PC, .MPG (short for MPEG) which is platform-independent, but requires its own player and .MOV and .QT for QuickTime movies which were initially just for the Macintosh, but are now available for Windows and UNIX.

avi

(pronounced avee)

Audio Video Interleave file format for Microsoft's Video Windows standard.

fla

(pronounced flash)

FLAsh Macromedia's FLASH working movie file. Upon completion of the Flash animation movie, the file is exported from FLASH as an .swa movie file. As an .swa file, the movie is no longer editable.

mpg
or mpeg

(pronounced m-peg)

Moving Picture Experts
Group
digital video compression format that achieves a high compression rate by storing only the changes from one frame to another, instead of each entire frame (as in fli/flc). The video information is then encoded using a technique called DCT. MPEG uses a type of lossy compression, that is generally imperceptible to the human eye.
MPEG-1 standard provide a video
resolution of 352-by-240 at 30 frames per second (fps). This produces video quality slightly below the quality of conventional VCR videos.
MPEG-2: offers resolutions of 720x480 and 1280x720 at 60 fps, with full CD-quality audio. This is sufficient for all the major TV standards, including NTSC (National Television Standard of Colors, and even HDTV. MPEG-2 is used by DVD-ROMs. Requires significantly more processing
power.
MPEG-4: will be based on the QuickTime file format.

(AUDIO) mpg
or mpeg

(pronounced m-peg)

Moving Picture Experts
Group

MPEG Audio: basically it is the sound layer of an mpeg movie file. Currently seen as:.mp, .mp2, .mp3, .m1a, .m2a, .mpg, .mpeg, .swa. MPEG also stands for the "Moving Picture Experts Group". MPEG audio files can be either layer I, II or III. Increasing layer numbers add complexity to the format and require more effort to encode and decode. However, they also provide higher playback quality for the sample bit rate. Audio MPEG files come in two flavors, MPEG-1 and MPEG-2. The encodings for the three layers are mostly the same; however, MPEG-2 streams have lower sampling rates for better fidelity at lower bit rates. Files can have sampling rates of 32000, 44100 and 48000 Hz for MPEG-1 and 16000, 22050 and 24000 Hz for MPEG-2.Microsoft has adopted the MPEG-2.5 "standard" for use in their NetShow product and also in WAVE files using the NetShow codec. MPEG data can be in stereo or mono and decompresses to 16-bit resolution. MPEG compression is a lossy algorithm based on perceptual encodings, which can achieve high rates of compression without a noticeable decrease in quality. Typical compression rates are around 10-to-1.

mov

(pronounced movie)

(.qt, .moov, .movie)

MOVie QuickTime Movies: (.mov) This is the Apple/Macintosh standard for time-based multimedia files. Versions 1.x support moving pictures, sound and later versions support text. QuickTime 2.0 added MIDI tracks via a software synthesizer or external synthesizer in 2.5 and later. QuickTime 2.0 or later and the QuickTime Musical Instruments extension must be installed in order to play QuickTime MIDI files. SoundApp should be able to play and convert from most all audio compression formats, although QuickTime 3.0 doesn't support conversion from MPEG so SoundApp can't either. Files are compatible with IBM-based computers with a plug-in found in most current Internet browsers using QuickTime for Windows.

swa

(pronounced movie)

Shock Wave Audio Macromedia's Shockwave streaming audio file
     

Other sound files come in .AIFF (for Mac); .AU for Mac and UNIX; .WAV for the PC; and .RA for Real Audio, a proprietary system for delivering and playing streaming audio on the Web.

Other proprietary graphic file formats:

PICT, Startup-Screen, MacPaint, TIFF (uncompressed, packbits, CCITT3/4 and lzw), RIFF, PICS, 8BIM, 8BPS/PSD, JPEG/JFIF, GIF, PCX/SCR, GEM-IMG/-XIMG, BMP (RLE compressed BMP's also), ICO/ICN, PIC (16 bit), FLI/FLC, TGA, MSP, PIC (PC Paint), SCX (ColoRIX), SHP, WPG, PBM/PGM/PPM, CGM (only binary), SUN , RLE, XBM, PM, IFF/LBM, PAC, Degas, TINY, NeoChrome, PIC (ATARI), SPU/SPC, GEM-Metafile, Animated NeoChrome, Imagic, ImageLab/Print Technic, HP-GL/2, FITS, SGI, DL, XWD, WMF, Scitex-CT, DCX, KONTRON, Lotus-PIC, Dr. Halo, GRP, VFF, Apple IIgs, AMBER, TRS-80, VB HB600, ppat, QDV, CLP, IPLab, SOFTIMAGE, GATAN, CVG, MSX, PNG, ART, RAW, PSION, SIXEL, PCD, ST-X, ALIAS pix, MAG, VITRONIC, EPSF (with the
help of EPStoPICT), Meteosat5, Sinclair QL, VPB, j6i, ASCII, ESM, CAM, PORST, Voxel, NIF, TIM, AFP, BLD, GFX, FAX3, SFW, BioRad, PSION 5, KDC (only PPC), QNT, JBI, DICOM, FAXstf, SKETCH, CALS, EletronicImage, X-Face, NASA Raster-Metafile, Acorn Sprite, HSI-BUF, FlashPix.

Information compiled from Webopedia On-Line, UDI Latarre at www.why-not.com, Make Your Scanner a Great Design & Production Tool by Michael Sullivan, and AskJeeves.com. On-line Help in Adobe Photoshop and from my own teaching experience.