Since my first post about Papers 3, a reference and pdf-file management software, it has significantly matured to become one of if not the best in the field. The most recent addition (version 3.2.6) has been to make a Papers 3 library indexable by Spotlight. Although documents in a Papers 3 library can be searched by FoxTrot or from within the app itself, these solutions are not ideal for searching on the fly. Now you can find Papers 3 library documents directly from Finder.
Search is possible not only by the title or author but also by Papers’ other metadata such as keywords as shown in the example above. Clicking on a search result would open the document in Papers, but this helpful script allows opening the PDF document in Preview or another default program. I must admit, it was the first time I’ve used Apple Script and it took a bit of (enjoyable) learning. Now I have it installed as an OS Service so that I can open the PDF document by either right-clicking on it or through a keyboard shortcut.
So far Spotlight cannot index inside PDF documents stored in the Papers 3 library, it only indexes metadata (which include for example journal title, DOI, manual collection name etc.). The Papers support team can explain how these are mapped to Spotlight’s indexing fields. As far as I understand Papers 3 is working on adding some capacity of Spotlight searching inside the PDF files stored in the Library. I hope it could also be possible to search OpenMeta (OS X) tags which I routinely attach to PDF files before they are imported into Papers.