Adobe Illustrator Artwork (AI) is a proprietary

Proprietary software

Proprietary software is computer software licensed under exclusive legal right of the copyright holder. The licensee is given the right to use the software under certain conditions, while restricted from other uses, such as modification, further distribution, or reverse engineering.Complementary...

 file format

File format

A file format is a particular way that information is encoded for storage in a computer file.Since a disk drive, or indeed any computer storage, can store only bits, the computer must have some way of converting information to 0s and 1s and vice-versa. There are different kinds of formats for...

 developed by Adobe Systems

Adobe Systems

Adobe Systems Incorporated is an American computer software company founded in 1982 and headquartered in San Jose, California, United States...

 for representing single-page vector-based drawings

Vector graphics

Vector graphics is the use of geometrical primitives such as points, lines, curves, and shapes or polygon, which are all based on mathematical expressions, to represent images in computer graphics...

 in either the EPS

Encapsulated PostScript

Encapsulated PostScript, or EPS, is a DSC-conforming PostScript document with additional restrictions which is intended to be usable as a graphics file format...

 or PDF formats. The .ai filename extension

Filename extension

A filename extension is a suffix to the name of a computer file applied to indicate the encoding of its contents or usage....

 is used by Adobe Illustrator

Adobe Illustrator

Adobe Illustrator is a vector graphics editor developed and marketed by Adobe Systems. Illustrator is similar in scope, intended market, and functionality to its competitors, CorelDraw, Xara Designer Pro and Macromedia FreeHand....

.

Early versions of the AI file format are true EPS

Encapsulated PostScript

Encapsulated PostScript, or EPS, is a DSC-conforming PostScript document with additional restrictions which is intended to be usable as a graphics file format...

 files with a restricted, compact syntax, with additional semantics represented by Illustrator-specific DSC comments that conform to DSC's Open Structuring Conventions. These files are identical to their corresponding Illustrator EPS counterparts, but with the EPS procsets (procedure sets) omitted from the file and instead externally referenced using %%Include directive

Directive (programming)

In computer programming, the term directive is applied in a variety of ways that are similar to the term command. It is also used to describe some programming language constructs ....

s.

The AI file format was originally a native format called PGF. PDF compatibility is achieved by embedding a complete copy of the PGF data within the saved PDF format file. The same “dual path” approach is used when saving EPS-compatible files in recent versions of Illustrator.

Programs that support AI files

Aside from Adobe Illustrator, the following applications can edit .ai files:

• CorelDRAW
  CorelDRAW
  CorelDRAW is a vector graphics editor developed and marketed by Corel Corporation of Ottawa, Canada. It is also the name of Corel's Graphics Suite...
  
   (proprietary program) can natively edit this file format with some limitations.
• Corel Paint Shop Pro
  Corel Paint Shop Pro
  Paint Shop Pro is a raster graphics editor and, later in the series, a vector graphics editor for computers running the Microsoft Windows operating system that was originally published by Minneapolis-based Jasc Software. In October 2004, Corel Corporation purchased Jasc Software and the...
  
   (proprietary program) can natively edit this file format.
• FreeHand
  Macromedia FreeHand
  Macromedia FreeHand is a computer application for creating two-dimensional vector graphics that are oriented primarily to professional illustration, desktop publishing and content creation for the Web. FreeHand is similar in scope, intended market, and functionality to Adobe Illustrator, CorelDraw...
  
   (proprietary program) can natively open and edit .ai file format version 8 or lower. FreeHand will export to .ai version 7 format.
• Ghostscript
  Ghostscript
  Ghostscript is a suite of software based on an interpreter for Adobe Systems' PostScript and Portable Document Format page description languages.- Features :...
  
   (GPL-licensed program) can convert AI postscript files into various formats, and also allows programs that use Ghostscript such as GIMP
  GIMP
  GIMP is a free software raster graphics editor. It is primarily employed as an image retouching and editing tool and is freely available in versions tailored for most popular operating systems including Microsoft Windows, Apple Mac OS X, and Linux.In addition to detailed image retouching and...
  
   to import AI files.
• Inkscape
  Inkscape
  Inkscape is a free software vector graphics editor, licensed under the GNU General Public License. Its goal is to implement full support for the Scalable Vector Graphics 1.1 standard....
  
   (a free, GPL-licensed program) can import the old Postscript-based Adobe Illustrator format (up to AI ver.8) and AI files based on PDF (AI 9.0 and above).
• Skencil
  Skencil
  Skencil, formerly called Sketch, is a free software vector graphics editor, released under the GNU Lesser General Public License. Its first public version, Sketch 0.5.0, was released on October 31, 1998....
  
   (GPL-licensed program) also claims to have some AI support.
• sK1
  SK1 (program)
  sK1 is an open-source illustration program for the Linux platform that can be used as a substitute for professional proprietary software like CorelDRAW or Adobe Illustrator...
  
   (a free, GPL-licensed vector graphics editor) supports PostScript-based AI files up to AI ver. 9.
• UniConvertor (a free, GPL-licensed vector graphics translator) supports PostScript-based AI files up to AI ver. 9.
• Xara Xtreme
  Xara Xtreme
  Xara Photo & Graphic Designer is a 2D vector graphics editor created by the British software company Xara, which was acquired by German company MAGIX AG in 2007, and now operates as a wholly owned subsidiary. It was previously sold under the names Xara Studio, Xara X and Xara Xtreme...
  
    (proprietary program) has support for the format that is described as "working". Xara Xtreme for Linux has similar support.
• XnView
  XnView
  XnView is a cross-platform image viewer used for viewing, converting, organising and editing graphical & video files. It is free of charge for private, educational and non-profit organisations...
  
  , a freeware graphics format converter, claims to be able to read AI file formats, if the AI file was saved with the PDF compatibility option. It does not support all AI subformats.
• FlexiSign (Vector Program used in Signmaking) Can read AI files.
• EnRoute (Vector program for routers) Can read AI files.

Viewers:

• Adobe Reader can open .ai files for viewing if they are saved with the PDF compatibility option
• Adobe Photoshop
  Adobe Photoshop
  Adobe Photoshop is a graphics editing program developed and published by Adobe Systems Incorporated.Adobe's 2003 "Creative Suite" rebranding led to Adobe Photoshop 8's renaming to Adobe Photoshop CS. Thus, Adobe Photoshop CS5 is the 12th major release of Adobe Photoshop...
  
  
• Preview
  Preview (software)
  Preview is Mac OS X's application for displaying images and Portable Document Format documents. Like Mac OS X itself, it comes from NeXT's OPENSTEP operating system....
  
  can view .ai files

External links

• Adobe Illustrator File Format Specification—the official specification for the original EPS-based formats
• Ill2SVG.pl source
• Xara Xtreme
• Skencil
• XNView supported formats