Hi Linda,
PDFs are made up of different "boxes". There is a Media box, which represents the paper size you are using. The Trim box represents your document size. The Bleed box, of course, represents your bleed info. Crop box = cropping of the PDF if there is any. And finally there is the Art box which contains the content of the PDF, images text etc. All of these boxes can have different sizes and are invisible unless you are viewing the PDF in Acrobat and you are using a page geometry editor or a plug-in like PitStop.
So, for example, if my document/trim size in Quark is 8 X 10.875 I will usually set my paper/media box size to 9.5 X 12 when I am making a Postscript file so that all my marks will show up.
When I make a PDF using the Postscript then Distill method, based on the example above, my media box size is 9.5 X 12 and my Trim box size is 8 X 10.875 which is exactly what I want.
When I export directly from Quark all of my boxes are the same size which is the final size as my PDF.
We recently switched from a Brisque to a Prinergy workflow. Prinergy is PDF based so all files that are brought into this worfkflow for loose proof output, imposition and plating are converted to PDFs either by Prinergy (in the case of PS, EPS, DCS files etc.) or as native PDFs. If the native PDFs do not have the correct trim box size set within the file the trim size has to be set manually with the Creo page geometry editor plug-in or through Prinergy. This is something that is very easy to do, but it adds an extra step to the process.
Whew!
Sorry if I went into too much detail on this one.
On a lighter note, if anyone has made it this far, what the heck is the SOFA? If you guys really need one I can probably pick one up at a garage sale this weekend.
:P
I will probably try asking this on some of the PDF forums as well.
Thanks again.