We are talking about some solutions at work for printing a summary generated from some interface content in an application. Many users may only want to print this out, but others would like the ability to save a file from the generated content.
Choosing "Adobe PDF" from the available printers dialog is a way of generating a PDF of the content. How well known is this concept? All of us at work, as well as some friends outside of work know how to do this, but is it common knowledge?
Print To File is the functionality you're referring to, and it's relatively new in common applications. I noticed Microsoft has started to promote it with their Print to XPS and Print to Onenote features for MS office. Print to XPS has the annoyance of being a new file format, Print to Onenote is amazing but you have to know onenote to get it.
In 4 years of college I met a great deal of people that were very surprised that I could "print" papers on my computer and mark them up in Onenote (this was largely before the popularity of the iPad, mind you), I would say it's a fairly foreign concept to a less adept user.
"Print" means paper to most people, they would consider what you're doing something different, saving or downloading a document/file. Most people who browse the web are familiar with such functionality. I would word it in that manner, and if possible present it as an alternative to printing, rather than treating it as a printing option (even though it is). You can present a dialog to select your print location, and show something like this:
Print: [printer dropdown]
[Print]
Or Save to PDF
[Save]
That way you present the options at the same time but avoid confusion. Depending on your menu setup "Save/download as" could be an alternate to "Print...". Google docs is a good example, their "Download as" menu lets you pick a file format similar to a printer menu, but keeping the dead tree options in the "Print..." item.
"Thou shalt speak thy user's language" :)
While "behind the scenes" it is just printing, your users are thinking in terms of converting a file to another format. I'm sure that even users who know to "print to PDF" can only identify it as "hmm, this has the word PDF, and there's nothing else with PDF, so this must be the one I need". So spare them a thought and set a menu item directly under the menu, not in a separate dialog box. "Export to PDF", or "save as PDF", or "convert to PDF" are ok. I'd not use "download to PDF" because it implies an Internet connection. Users may not have one at that computer, or they may think they need to pay for the "downloaded" bytes so they'll be wary of using the command.
You'll find something about the user's mental model in a similar situation in "GUI Bloopers", somewhere in the first 5-6 bloopers I think (I don't have the book here right now, sorry).
I think that users who are sophisticated enough to want to save as a local file, and know how to handle local files, could probably deal with PDFs.
I once did a similar thing but "printing" to a high res PNG. That's an option, too.
I do not have an opinion about whether the users of your application are aware that they can create a PDF by choosing "Adobe PDF" from the available printers dialog. I believe, in general, most users are not aware that feature. I also believe, in general, most users understand that a button labelled something like "Download to PDF" will create a PDF file for them.
This sounds like a good subject for a usability test.
