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chirpy22 · Apr 19, 2008, 02:58 PM

if Adobe Illustrator files are PDFs, why can't Mac OS X display their previews as it does with regular PDFs?

64stang06 · Apr 19, 2008, 04:43 PM

I thought the default format for Illustrator was a .ai file?

Chuckit · Apr 19, 2008, 05:58 PM

Originally Posted by 64stang06

I thought the default format for Illustrator was a .ai file?

".ai" is a file extension, not a format. There have been a couple of different formats contained in ".ai" files, one of which is PDF. I assume Apple didn't include ".ai" for the Quick Look PDF plugin because it wouldn't work with some files. Or maybe they just thought Adobe should do it. I don't have any inside info.

64stang06 · Apr 19, 2008, 06:26 PM

Originally Posted by Chuckit

".ai" is a file extension, not a format. There have been a couple of different formats contained in ".ai" files, one of which is PDF. I assume Apple didn't include ".ai" for the Quick Look PDF plugin because it wouldn't work with some files. Or maybe they just thought Adobe should do it. I don't have any inside info.

That's what I meant. Was stuck on the proper word. Thanks

Andrew Stephens · Apr 23, 2008, 05:18 PM

surely .ai is a file extension that indicates a file is in Adobe Illustrator native file format. native ai files are NOT pdf files.

Saving an illustrator as a pdf assigns it the file extension pdf since it is then encoded in the pdf file format. Illustrator pdf files show up in quick look just fine.

TETENAL · Apr 23, 2008, 05:40 PM

Originally Posted by Andrew Stephens

surely .ai is a file extension that indicates a file is in Adobe Illustrator native file format. native ai files are NOT pdf files.

Yes, they are (although the opposite is not true ).

kga1978 · Apr 24, 2008, 03:12 PM

I have been wondering about this as well. The fact is that if you change the extension ".ai" to ".pdf" then it can be read with coverflow and quicklook..... which means that it is clearly supported - why Apple hasn't included this then, I really don't know!

Don Pickett · Apr 24, 2008, 07:34 PM

Originally Posted by TETENAL

Yes, they are (although the opposite is not true ).

No, they're not. Open an .ai file in a text editor and you will see a lot of "AIPrivateData" statements, which are essentially non-PDF extensions to the data which support things which PDF doesn't support: layers, paragraph and text functions, brushes, etc. These statements are stripped out when you save as a .pdf, which is why .ai files which are saved as .pdf files and then opened in Illustrator look strange.

The two file types are very similar, though, down to both starting with "%PDF-1.X". It's probably fairer to say that. at some point, Adobe ditched the old .ai format and decided it was easier to take .pdf, extend it internally and not document it.

chirpy22 · 11:16 PM

PDF files support layers.
It just seems strange to me that quicklook won't let you see them. You can view them fine in Preview. When you save an AI file you just need to make sure that the PDF compatible checkbox is checked.

Don Pickett · Apr 24, 2008, 11:25 PM

Originally Posted by chirpy22

PDF files support layers.
It just seems strange to me that quicklook won't let you see them. You can view them fine in Preview. When you save an AI file you just need to make sure that the PDF compatible checkbox is checked.

It can display them, but it can't manipulate them like Illustrator can. Hence the need for the extension in the .ai file.