When you save as PDF with the editing capabilities, you actually get a PDF and an AI, but you can alo save without them so you only get the PDF, with the corresponding loss.
So you can get:
AI only with AI,
Both with PDF,
PDF only with PDF.
PDF files can have bleed.
> What is the big difference between saving as an .ai versus saving as a .pdf.
That depends on whether you leave the default settings on. If you do, you are really saving two full and distinct copies of the entire content in one file, and the "difference" between the two files is mostly marketing-inspired hype. But if you turn off the default setting to include BOTH versions of the file, then the difference is real. AI and PDF content is not the same thing.
The two default options I refer to are:
Create PDF Compatible File (when saving as AI)
Preserve Illustrator Editing Capabilities (when saving as PDF)
> I like the flexibility of saving as a .pdf so that people w/o illustrator can view my comps.
That's fine. But you are really saving two complete versions of the file's content, and the PDF you are sending to your non-Illustrator recipients is much larger than necessary. That's because the PDF, by Illustrator's default, also contains another complete copy of the file in Illustrator format, which is ignored by Reader.
> I know if I save as a .pdf (versus printing or exporting), I can reopen the .pdf and still have all my editing capabilities there (that i know of).
That's fine, too. But again, that's only because you are, as stated above, saving a PDF that also contains a complete second copy of the content as Illustrator-native objects. When you open that PDF in Illustrator, Illustrator loads the native-ai content, not the PDF content.
> Can someone enlighten me?
Despite confusing marketing hype to the contrary, PDF and Illustrator formats are not the same thing.
PDF is basically like capturing the artwork halfway on its path to a PostScript printer. Illustrator-specific constructs like live blends, multiple fills, multiple strokes, (and much more), are dumbed-down to simpler discrete objects.
But a PDF file can contain a "cordoned off" area that can contain just about any kind of data a programmer wants to insert there, but which is altogether ignored by Reader. Think of it like inserting a comment statement in a code file. That extra data, of course, makes the file larger.
Similarly, Adobe changed Illustrator's format a while back to also include a "cordoned off" area that can contain PDF data. Again, that extra data makes the file larger.
When you save as PDF in Illustrator, you are saving the content of the file as "dumbed down" PDF content that can be understood by Reader. But when doing so, if you also leave the default "Preserve Illustrator Editing Capabilities" checkbox on, you are also including a full copy of the file in Illustrator's native format in that "marked off" area inside the PDF. So if a recipient using Reader opens the PDF, Reader loads the PDF content and ignores the "marked off" content. If you open the PDF in Illustrator, Illustrator checks to see if you also stashed away AI-native content in that "marked off" area. If it finds that you did, it opens that version of the content, not the PDF version.
Inversely, when you save as AI, you are saving the content of the file as the fully editable Illustrator-specific constructs. But when doing so, if you also leave the "Create PDF Compatible File" checkbox on, then you will also be including another copy of the same content dumbed-down to PDF objects, and stored in .ai format's "marked off" area. If you then, for example, Place the .ai file in InDesign, InDesign in fact imports the "hidden" PDF content, not the .ai content.
The problem is, this scheme has been marketed as "equality" between Illustrator's native format and PDF format, and that has led to needless confusion. It's as if saying:
A may contain B.
Therefore A equals B.
Which, of course, is bogus. According to what I have been told, Corel, for example, could hide its fully-native Draw content within the "marked off" region of a PDF exportd from Draw. Corel could then, I guess, similarly claim that Draw and PDF are "equal."
Open an Illustrator file. Make sure it contains some Illustrator-specific content, like a live Blend and a multi-line AreaType object. Save it as PDF, but turn off the Illustrator Editability checkbox. You have now exported the file as PDF content. Now open the PDF in Illustrator. It will open, because Illustrator can understand the simpler objects. But you'll find that the Blend is not an AI blend at all; it's just a stack of individual paths. The text object will be multiple textFrame objects, not one AreaType object with auto-wrapping text.
Now go back to the original AI document. Save it as AI, but turn off the Acrobat Compatibilty checkbox. Launch InDesign and try to Place the .ai file. InDesign will tell you it can't place the file. That's because InDesign can't really place .ai content. It can place PDF content, but there isn't a PDF version of the content in the .ai file you are trying to place.
> I like the flexibility of saving as a .pdf
That's fine, so long as you are not fooled by the smoke-and-mirrors. If you allow yourself to go on thinking that PDF and AI are actually "the same thing," you'll be scratching your head as soon as you open a PDF that doesn't happen to also contain a stashed-away version of itself in .ai-native format. (For just one example, if you ever happened to open a PDF saved by me.)
This is similar to another (in my opinion, equally ill-conceived) smoke-and-mirrors "equality" scheme, this time involving Macromedia's (now Adobe's) Fireworks.
Fireworks contains vector drawing tools. You can draw vector paths in Fireworks, save the file, open it later, and further manipulate the Fireworks-native vector paths.
But Firework's "native" format is PNG, which is a non-proprietary, open standard, raster format.
But a PNG file can include a "marked off area" to contain pretty much whatever a programmer wants. So Macromedia, capitalizing upon the popularity of PNG, made it the "native format" of Fireworks, and didn't even give Fireworks its own unique file extension. The vector Fireworks-native content goes in the "marked off" area, and gets rasterized to the normal PNG area that other raster image programs can see.
1. You open Fireworks and draw a vector object. Save the file as MyVectorArtwork.png.
Now. Other programs can, of course, open PNGs. So...
2. You open the PNG in a raster image program and edit the image. (Add a red square). Save the file.
3. Open the file in Fireworks. Fireworks reads the marked-off Fireworks-native content. Your vector path is there. But where is the red square?
Consequently, now that Adobe has acquired Macromedia, schitzophrenic Adobe is stuck with two contradictory smoke-and-mirror schemes:
In the Illustrator/PDF scheme, two different kinds of content are saved as two ostensibly "equal" file types.
In the Fireworks/PNG scheme, two different kinds of ostensibly "equal" content are saved as one file type.
All of which, of course, is "justified" by the original "nobel" intent to "simplify" things for the "benefit" of the "stupid" users of the programs.
Not to worry, though. Adobe will "fix" all this cross-application confusion in CS4 by making all the programs conform to the "unified" user interface (i.e.; window/palette dressing), thereby resulting in a "seamlessly integrated" suite of programs.
Thats interesting. For a long time I was told that as of version 9 of illustrator, the format was switched to pdf. Which was why some programs could no longer import ai files.
BTW thanks for clearing up png files, that one had me confused.
So if it saves basically the ai and the pdf info into 1 pdf file, why is the file size of the "save as pdf" so much smaller than the ai.
my native ai file = 1.12MB
save as pdf (preserving Illustrator capabilities) = 343KB
save as pdf (not preserving Illustrator capabilities) = 130KB
Should I start saving my source files as "save as pdf (preserving Illustrator capabilities)" since it is a smaller file size, therefore saving me some space and allow others without AI to view my comps?
I keep the AI and PDF files as completely separate things. The AI files contain no PDF and the PDF files contain no AI. I view AI files strictly as source files for generating PDFs. It eliminates much confusion about which is the current version and also helps prevent PDFs from being edited by well-meaning, but often less-than-competent third parties who happen to have Illustrator. I supply AI files to very, very few people, but PDFs to many. The difference in file sizes makes the PDF versions easier to email and allows me to adjust the level of PDF fidelity depending on the purpose. My printer gets Press Quality, while proofreaders get Smallest File Size.
I, on the other hand, usually save PDFs without AI content, but save AI with PDF content.
I don't need AI content in a PDF. If I want to send something fully editable in AI, then (duh), it's assumed the recipient has AI; I send an AI file.
However, saving AI with PDF content allows me to place the AI file in InDesign. Yes, it's acutally the PDF content that gets imported, but the Edit Original feature works.
>However, saving AI with PDF content allows me to place the AI file in InDesign. Yes, it's acutally the PDF content that gets imported, but the Edit Original feature works.
As well as preview in Finder on a Mac or other PDF savvy software, like browsers.
Generally I'm happy to leave PDF compatibility checked unless the size become problematic. 480 MB with PDF compatibility vs 472 KB without. That means a Save can take either 5 minutes or a couple of seconds. Since Illustrator tends to crash more frequently than Ricky Bobby, any disincentive to save is asking for trouble.
So just to bump this thread I imported a 72K jpeg (linked) into a ai file and then saved it in numerous permutations. The only really small file sizes came from distilling a print to postscript file. The permutations were one image as linked or embedded or as a symbol (use_type) one instance or 6 instances of image (one/many) and saving as ai (no PDF content) or PDF (no ai content) or Distilling a postscript print file (doc_type).
So I guess that makes:
P = (use_type) . (one/many) . (doc_type)
= 3 x 2 x 3
There are 20 different versions plus 2 distiller files in the results. I did it a couple of times with slightly different scales on the jpeg object so maybe that is resulting in small size differences for same permutations done twice (difference in image compression). I kept all image compression and page thumbnails, colour profiles etc. off with exception of file compression for .ai files (it's on).
I included symbol instances because an adobe sales manager/trainer/evangelist told a group of employees I was contracted to train to use symbols for multiple instances of images (saying this was a new feature but when I said isn't that just like a brush or linked image he said yeah same result: OO embedding, guess he was trying to idiot proof the process rather than educate in a short space of time). Symbols result in bigger files than linked but are preferable to multiple embedded files.