Why does Preview not display some PDF content which is visible in Adobe Acrobat?

The answer is that some pdf options are not available in Preview. Adobe has a number of annotation and graphics and even file linking options which do not carry through to Preview. In other words, Preview is not 100% compatible with Adobe Acrobat, Preview is less capable, although it can generally handle probably 99% of what people do in pdf format. But there is a small collection of things that do not come through properly with Preview.

One obvious example is forms. While this may not be the situation you are asking about, note that Adobe Acrobat can create forms that one can fill out with Acrobat Reader. These forms have cells and one can go through them and enter text or information into those cells with Adobe's software. Sometimes the forms even include boxes to be checked or highlighted and so forth, all possible with a click using Adobe's own software. However Preview often is unable to enter the data on those forms. Again, the reason is that for certain somewhat advanced options, Preview does not have every capability that Adobe Acrobat (or Acrobat reader) has.

For simple stuff, however, Preview generally works well.

It really isn't that Preview is less-robust, it is that Acrobat is always changing the rules. Adobe is pretty much constantly working on new versions of Acrobat. When they come up with one, they make that the new default version. Apple tries to keep Preview up to date, but it is always a moving target.

Apple tries to keep Preview up to date, but it is always a moving target.

Yup, and on top of that, Apple has to essentially reverse engineer what has changed in Acrobat so they can emulate it. Apple usually figures it out, but not always.

Hi James

I've come across several like that, & just hope it's usually obvious when something's missing. Some display a clear message - use Adobe Reader, but others don't, as you describe.

I have not found a way to see the missing content in Preview.

In the same boat here. Some small percentage of PDFs (from the same people) won't be complete when viewed in Preview. Sometimes they are blank; sometimes some text is missing. Seems a font problem, but we've tried changing fonts and that didn't fix it. As above, opening in Adobe Reader works. And, one thing I've not seen mentioned on any other threads, the documents show up fine in iOS (iPhone 3GS and iPad). Hoping someone smarter than I posts the answer.

Thanks

EB

I would generally concur with what you said re: Preview's less-robust status. However, in my case, the issue is not always complicated things (e.g., not being able to see mark-ups on PDFs), but rather pure-text Word docs that are PDFed. That's what puzzles me the most.

Kurt Lang wrote:

Yup, and on top of that, Apple has to essentially reverse engineer what has changed in Acrobat so they can emulate it. Apple usually figures it out, but not always.

Adobe publishes those changes to the PDF standard, but not until they release a new version of Acrobat. Plus, they don't always conform to the standard themselves - as we all know from MacOS X 10.6.7.

Changes to the PDF structure can apply to basic elements too.

If you have a PDF that Preview has problems with, you should always save it and submit the PDF to Apple via a bug report.

Plus, they don't always conform to the standard themselves - as we all know from MacOS X 10.6.7.

That's true. 🙂 It doesn't do other vendors any good to write their updates to follow the standards, when Adobe's actual software doesn't work that way itself.