Difference between EPS file and AI file

[Eynat Segal]

Hi,

Why would you want to save an illustrator file under either one of these extensions. What is the main difference?

Thanks in advance,

Nati

[Harry Naul]

eps is expected by typograph companys, printing books and magazins, because they are using this format directly - it is able to keep original form of the picture, included fonts used inside etc..

[Ian A. Wright]

Eynat:

EPS (Encapsulated PostScript Files) are strange bunnies. When you import them into your DTP or presentation program, they behave differently than the other imports you're used to. Here's the Why and Wherefore.

First of all, EPS is NOT the same as PostScript (such as you'd produce by printing to disk using a PostScript driver). It can contain nearly all the same commands and graphics as a regular PS file, but some PS operators are strictly verboten in EPS. Moreover, EPS contains no page setup information and might not contain a "showpage" command ... the PS equivalent of "Print 'em, Dan-o". An EPS may print if you send it to a PS printer, but it may not. Them's the breaks.

Neither is EPS the same as AI, or Adobe Illustrator format. The old version of the .AI format was a very restricted subset of EPS intended for importing apps to translate into their own format. The NEW version of the .AI format (since AI9) is now a form of PDF which allows transparency and other neat effects.

An EPS file contains one image only; in other words, it cannot contain multiple pages, but each image may be made up of several other images.

Some EPS have very low resolution, low quality previews, others may have full-color, high resolution preview images or even fully scaleable vector WMF previews. If you print an EPS to a non-PostScript printer all you'll see is the header unless the application has a built-in software RIP like Illustrator and InDesign.

And,unlike .AI files, EPS are NOT meant for editing -- only printing.

(Adapted from a diatribe by Steve Rindsberg)

[LenHewitt]

Natin

Just to add a little to Ian's explanation....

Very few applications will allow you to Place or import an .AI File whereas
many applications will allow an EPS file to be placed/imported.

When an EPS is placed in another application, that application does nothing
with it - it merely includes the contents of the file into the print stream
when the document is output.

.AI is Illustrator's "native" file format. It used to be very similar to the
EPS format, but is now a form of PDF, the format that Acrobat uses. By
saving as .AI (or PDF with "Preserve Editing Capabilities checked) you
preserve ALL possible Illustrator facilities - e.g embedded ICC profiles.

(Why Illustrator's EPS's don't support embedded icc profiles. I just don't
know - the EPS format supports them, it is just Illustrator that doesn't)