Adobe Illustrator Artwork

Adobe Illustrator Artwork (AI) is a proprietary vector graphics format used by the Adobe Illustrator program.

The original format of these files was known as "PGF", but it was later embedded in a PDF wrapper for compatibility with that format, but includes AIPrivateData tags. The format is also related to Encapsulated PostScript (EPS), and some versions of the file format are made to be compatible with that. Some forms of the file have multiple versions of the data embedded in it for multi-format compatibility.

Identifiers
Version 1-8 (EPSF) Version 11(CS) - 16(CS6) Version 17(CC) Version 24 (2020)

Specs

 * 1992 Adobe Illustrator file format specification
 * 1998 Adobe Illustrator file format specification

Sample files

 * https://telparia.com/fileFormatSamples/image/adobeIllustrator/

Other links

 * Wikipedia: Adobe Illustrator Artwork
 * Wikipedia: Adobe Illustrator
 * , from the Encyclopedia of Graphics File Formats
 * The Adobe Illustrator Story (video)
 * Adobe Illustrator to HTML open-source script
 * Illustrator 9 PDF Compatibility
 * Difference between an AI file and PDF
 * Support for Type 1 fonts dropped in 2023