Graphic File Formats

Native Files    For print    For WEB 
 
 

File Formats

The specific format in which an image file is saved. The format is identified by the three letter extension at the end of the file name. Every format has its own characteristics, advantages and disadvantages. By defining the file format it may be possible to determine the number of bits per pixel and additional information.

Native File Formats

Native files are saved in the default format belonging to the application with which they were created. 
 
EXT Description

PSD 

Adobe Photoshop Document
QXD Quark Express Document
AI Adobe Illustrator file 
   

File Formats for Print
 
EXT Description

EPS

Encapsulated PostScript 

The Encapsulated PostScript file format is supported by most illustration and page layout programs, and in most cases is the preferred format for these applications. Note that this is also the only file format that supports transparent whites in Bitmap mode. This format contains raw PostScript along with a low resolution screen PICT preview.

 

PS Raw PostScript file

A page description language which includes text as well as vector graphics and bit-mapped images. This format is text-only and contains no screen preview. 

 

TIF TIFF (Tagged-Image File Format) 

Mainly for exchanging documents between different applications and different computer platforms. The Tagged Image File Format was primarily designed to become the standard format.

The TIFF format supports LZW method compression for image types. (This is the same compression used by the GIF format for indexed color.) 

 

PDF Portable Document Format (Adobe Acrobat)

PDF files can be read on any computer that has Adobe Acrobat Reader installed. PDF file can be created from PS files using Adobe Acrobat Distiller, or can be exported from most image manipulation and and page layout applications.

http://www.macinstruct.com/tutorials/pdf/index.html

 

File Formats for WEB
 
EXT Description

GIF

Graphics Interchange Format 

Created by CompuServe to upload documents to the CompuServe Information Service and to pass documents between other types of computers. 

The idea behind designing GIF files was to create the smallest possible image file for uploading and downloading from electronic Bulletin Board Systems (BBS), thus producing a highly compressed format that minimizes file transfer time over phone lines. The compression is accomplished by using the LZW method for indexed color tables. 
 

JPG JPEG (Joint Photographic Experts Group)

JPEG compression economizes on the way data is stored and also identifies and discards extra data, that is, information beyond what the human eye can see. Because it discards data, the JPEG algorithm 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 image. In most cases, the difference between the original and compressed version of the image is indistinguishable. In general, compressed JPEG images have compression ratios of between 5:1 and 15:1. A trade-off does exist between the image quality and the amount of compression. You do not need to decompress images saved in the JPEG format. They are automatically decompressed when they are opened. 

   

Links

http://www.why-not.com/articles/formats.htm

http://www.cywarp.com/FAQ_TimeCapsules.asp?goto=162

http://www.program.com/resources/graphics_format.html

 

 

Top of Page    Native Files    For print    For WEB