Digital Photo File Formats

JPEG (or JPG)

Acronymn: Joint Photographic Experts Group

Best use: A JPEG is good in any situation. It is viewable by all web browsers and image-editing programs.

Compression type: Lossy

Colour type: 8-bit grayscale and up to 24-bit colour

Note: compression amount is configurable, but a highly compressed image will permanently degrade image quality when uncompressed for viewing or printing.

GIF

Acronymn: Graphics Interchange Format

Best use: GIF is best reserved for display on the web. It is viewable by all web browsers.

Compression type: Lossy

Colour type: up to 256 colours

Note: the biggest limitation here is number of colour possible, but the size of image is typically smaller than a JPEG. Transparency is possible using GIF, and GIF images can be animated.

TIFF

Acronymn: Tagged Image File Format

Best use: TIFF is best for print images. When high quality prints are required, it is best. Web browsers do not read this image type.

Compression type: can be lossless

Colour type: RGB, CMYK, LAB; up to 64-bit colour

Note: TIFF images can contain multiple images within, but be aware that image size is much larger than compressed JPEG.

EPS

Acronymn: Encapsulated PostScript

Best use: EPS is the standard prepress printing format supported by QuarkXPress

Compression type: can be lossless

Colour type: RGB, CMYK, LAB; up to 64-bit colour

Note: EPS images contain two pieces: instructions for the printer, and a preview image of type PICT, TIFF, or JPEG.

BMP

Acronymn: Bitmap (Microsoft Windows)

Best use: Quick view on a PC computer. If you ever copy an image to clipboard, it will be in Bitmap format.

Compression type: bit-depth specified by custom user settings on the PC

Colour type: RGB, Indexed colour, grayscale

Note: This file format results in an file size slightly larger than JPEG. Clipboard images are stored as .clp files.

PDF

Acronymn: Portable Document Format

Best use: Viewing a document without the application that created it installed on your PC, or to put a text caption beside it.

Compression type: proprietary to Adobe

Colour type: 4-bit grayscale, 8-bit colour, up to 64-bit colour

Note: This file format is only readable by Adobe Acrobat products (the Reader is free). It is not an image file format specifically, but it allows a file to be read on any computer since the Reader works on all platforms.

RAW

Acronymn: RAW is actually not an acronymn; instead, it refers to unprocessed image data.

Best use: Capturing images on camera that may need white balance modifications post-capture.

Compression type: not compressed

Note: A RAW image file contains minimally processed data from the image sensor of a digital camera or image scanner. It must be processed with special software designed for the particular implimentation of of RAW used by the camera before it can be manipulated. File size is up to 6 times larger than the same image captured in JPEG format.