Cookies for analytics and advertising
We use cookies for analytics and advertising, both sent to Google. Refusing changes nothing you can see.Read the privacy page
AI
What is an AI file?
Illustrator working files. Modern versions are PDF underneath, which is what makes them readable at all.
What AI is
AI is a document format, describing pages rather than pixels. It stores shapes and coordinates rather than pixels, so it stays sharp at any size — a logo scaled to a billboard loses nothing. It is used for print, editing and line art and logos.
The extension is .ai, and the full name is Adobe Illustrator Artwork. Both matter less than what the file can hold, which is what the rest of this page is about.
Where AI came from
Adobe published it in 1987.
A format that has been readable for that long is a format worth trusting with something you want back in ten years.
The specification belongs to its vendor
Reading it outside the vendor’s own software depends on work done by other people, usually by inspection rather than by documentation. That mostly works and occasionally does not, which is the reason to convert anything you intend to keep.
Nothing is thrown away
AI stores its content exactly. Saving it again changes nothing, so it can be opened, edited and re-saved as often as you like without accumulating damage — which is what makes it a working format rather than a delivery one.
It can be transparent
AI carries an alpha channel, so a logo keeps its soft edges over whatever sits behind it instead of arriving in a white box.
Colour it can describe
It can work in RGB and CMYK, the model a printing press needs.
CMYK is the one that decides whether a printer accepts the file, and it is the thing most often lost converting to a screen format.
It can hold several pages in one file
A AI file is not limited to one page, which matters when converting to something that is: a target that holds one image produces one file per page, and the numbering it chooses is worth checking before you send it on.
It keeps the layers
AI stores the parts of an image separately rather than flattened together, which is what makes it a working file. Almost every format it converts into flattens them, and the flattening is not reversible — keep the layered original.
What opens AI
Adobe Illustrator reads it, and so do most programs of the same kind.
If a file will not open, the format is rarely the problem — it is more often that the program predates it. Converting to something older is the reliable way past that, and it is what the rest of this site is for.
Opening it in a browser
No browser reads it.
That is the single most common reason to convert it: not that the format is bad, but that the place you want to show the file cannot read it.
It is a working format
AI is meant to be opened and changed. Keep the file in this format for as long as the work is going on, and export from it whenever a finished copy is needed.
What goes wrong with it
The recurring complaints: support outside its home ground is uneven.
None of these is a reason to avoid the format. They are the things worth knowing before you are surprised by one, which is a different claim and a more useful one.
The facts, in one place
| Extension | .ai |
|---|---|
| Media type | application/illustrator |
| Published by | Adobe |
| First published | 1987 |