File Formats by Michael Kroeger

About file formats uses various sources for information including the Adobe Photoshop 4.0 User Guide.

BMP is the standard Windows bitmap image format on DOS and Windows-compatible computers.

Photoshop EPS
The Encapsulated PostScript (EPS) language file format is supported by most illustration and pagelayout programs, and in most cases is the preferred format for these applications.

The Filmstrip format is used for animation or movie files created by Adobe Premiere.

CompuServe GIF
The CompuServe Graphics Interchange Format (GIF) is the file format commonly used to display indexed-color graphics and images in hypertext markup language (HTML) documents over the World Wide Web. GIF is a compression format that is designed to minimize file transfer time over phone lines.

The Amiga ™ Interchange File Format is used for working with Video Toaster and transferring files to and from the Commodore Amiga syster.

The Joint Photographic Experts Group (JPEG) format is commonly used to display photographs and other continuous-tone images in hypertext markup language (HTML) documents over the WWW. Unlike the GIF format, JPEG retains all the color information in the RGB image. JPEG also uses a compression scheme that effectively reduces file size by identifying and discarding extra data not essential to the display of the image. Opening a JPEG image automatically decompresses it.

Because it discards data, the JPEG compression scheme is referred to as lossy. This means that once an image has been compressed and then decompressed, it will not be identical to the original.

The MacPaint format is commonly used to transfer Bitmap-mode images to Macintosh applications.

PCX format, established by Z-Soft ® for its PC Paintbrush ® software, is commonly used by IBM PC -compatible computers.

The PDF format is used by Adobe Acrobat ®, Adobe's electronic publishing software for Macintosh, Windows, UNIX ®, and DOS. Based on the PostScript Level 2 language, PDF can represent both vector and bitmap graphics. For the purposes of representing pages, PDF pages are identical to PostScript pages, but PDF files can also contain electronic document search and navigation features. PDF files, for example, can contain hypertext links and an electronic table of contents.

The PICT format is widely used among Macintosh graphics and page-layout applications as an intermediary file format for transferring files between applications. The PICT format is especially effective at compressing images that contain large areas of solid color.

The PIXAR format is designed specifically for exchanging files with PIXAR image computers. PIXAR workstations are designed for high-end graphics applications, such as those used for three-dimensional images and animation.

The PNG format was developed as an alternative to the GIF format and, like GIF, is used for displaying images on the WWW. PNG preserves all color information and alpha channels in an image and uses a lossless compression scheme to reduce file size.

The Raw format is a flexible file format for transferring files between applications and computer platforms. Raw format consists of a streem of bytes describing the color information in the file.

Scitex CT
The Scitex Continuous Tone (CT) format is available for RGB and CMYK images and grayscale images. Scitex computers are used for high-end image processing. Images in Scitex CT format are CMYK files that are often extremely large in size. The files are printed to film by using the Scitex rasterizing unit (RIP).

The TGA (Targa) format is designed for use on systems that use the Truevision ® video board and is commonly supported by MS-DOS color applications.

The Tagged-Image File Format (TIFF) is used to exchange files between applications and computer platforms. The TIFF format supports LZW compression, a lossless compression method that does not discard details from the image.

When you save an image in TIFF format, you can choose to save in a format that can be read either by Macintosh or by IBM PC-compatible computers. You can choose to compress the file to a smaller size automatically by clicking the LZW Compression check box.

Adobe Photoshop reads and saves captions in TIFF files. This feature is of particular use with the Associated Press Picture Desk system, which uses thw same TIFF caption fields.

Copyright © 1996--2002 MK Graphic Design. All rights reserved. No portion of this document may be copied, reproduced, or electronically reused without written permission from Michael Kroeger at MK Graphic Design. (11.26.02)