I think it's worth mentioning that Robert "groups, objects, whatever -- they're all really layers" Prey, in his haste to discredit Jay at all costs, managed to miss the important detail in the sentence he quoted
"...even though a portion or even a whole
object may reside on different document
layers, Acrobat views the object as a single item for selection and editing."
http://pdf-tips-tricks.blogspot.com/2009/03/editing-document-layers-in-pdf-file.html
That is, here the distinction is drawn between
objects as editable entities, and
layers which are simply containers. Robert can't make up his mind whether objects
are layers, or objects are
in layers. He changes his mind depending on what he Googled today. If you've followed my explanations so far, I've laid it out repeatedly in great detail. In Ps, layers
are displayable data objects. In Ai, iD, and Ac, layers are containers that
hold displayable data objects. This is important when you remember that Mara Zebest says the document was initially created in Photoshop and exported as a "layered" PDF.
Now in Illustrator, those are the underlying concepts -- layers and objects. In PDF 1.6, which applies to the Acrobat instructions he posted, "layer" is simply the manual's term for the underlying optional-content group mechanism, which I've talked about at length, and which in fact doesn't exist in PDF 1.3. And to be sure, the sentence he quotes specifically discusses the peculiar behavior of OCGs in PDF files -- that an object may actually be in one
or more such groups. Not so in Illustrator etc., and completely irrelevant to Photoshop.
Now let's be scrupulously responsible: Robert specifically expects his Acrobat manual quote to vindicate his question, "would it not be accurate to say that "groups" or "objects'" reside on layers????"
I responded that this was inaccurate, and it's still inaccurate. In order for Robert's interpretation of the Illustrator display to make sense, all objects would have to be in their own layer.
Have to be, as in a hard-and-fast requirement. As I mentioned, no displayable data object exists in Illustrator outside of some layer.
As late-version Acrobat users can attest, objects need not be in
any layer. Or they can be in
all the layers. Or there may not be any layers in the document. All those are true possibilities in Acrobat, but have no bearing on any other Adobe product. That's because the "layers" you're editing in Acrobat are optional-content groups. That is
optional. They aren't Photoshop layers. They aren't Illustrator layers. They exist only for Acrobat. Yes, objects in PDF files
may be in OCGs, but are not required to be, as would have to be the case if Robert is reading Illustrator properly. The layering model for PDF is entirely dissimilar from the layering model in any other Adobe product.
If Robert had actually read any of my analysis, instead of trying so hard to tell you it was mere technobabble, he'd have learned that the "layers" (i.e., OCGs) you create in Acrobat don't show up as layers in any other product. As usual, importing a PDF into those products creates
one layer with several constituent objects. Those objects do not each reside in their own layer, as Robert is frantically trying to make you believe. By default they are
imported into the default first layer Illustrator demands.
And yes, we've all empirically verified this.
And no, the OCG-based layering abstraction in Acrobat that Robert has lately hitched his star to has absolutely no relevance to Obama's PDF 1.3 document. Robert can demonstrate this to himself by creating "layers" in Acrobat, saving the result as a PDF 1.3, and seeing whether those layers show up again when he re-opens the document in Acrobat.
