The most common use of ‘PDF preview’ does imply an illegible file.
But what you suggested isn’t a bad idea in itself, although you have overly generalized about what is and isn’t useful in a database. I often use a PDF version of an ‘unknown’ file type as a surrogate, and place the path to the unknown file in the PDF’s Info panel URL field.
In many instances, however, I find it useful to capture unknown file type material, such as a collection of Excel spreadsheets related to a project, without a PDF counterpart file.
That’s because DT Pro has captured metadata about the unknown file. The metadata is searchable, and I can add to it, perhaps with a script to add descriptive information to each member of a collection of Excel sheets. For purposes of using the documents, descriptive or explanatory metadata is often more important for searching and analysis than seeing the ‘actual’ content of the document.
The assumption that there’s no value to incorporation of ‘unknown’ files into a database is often wrong. If I’m working on a project that involves, for example, Excel sheets and a Powerpoint presentation, I import them. They are part of the project collection. I can search for them by name, file type and so on. Their organizational location tells me a great deal about why and how I included them. And I can add descriptive material to the metadata, often providing information that wouldn’t be evident even if I were looking directly at the sheet. If I wish to examine or modify the file contents, I can quickly open it under its parent application. There has been information value added by importing such ‘unknown’ files.
So I think it would be overkill and wasteful of storage space and memory to automatically duplicate every ‘unknown’ file that I choose to capture into a database.
“Choose” is the operative word in the above paragraph. I see little value in using DT Pro as a Finder/Spotlight replacement, because that doesn’t make optimum use of DT Pro’s capabilities to assist a user to manage and analyze the information content of a database.
There are many times when I do use PDF surrogates of an unknown file type to add data to a database. There’s a ‘print’ script for that purpose.
I would like to see some additional power to that script, if possible. For example, sometimes I would like to be able to access the original document directly from the PDF version. I can do that by entering the Path to the original document into the URL field of the PDF’s Info panel. Could an enhanced script do that automatically? That would be great.
I would like to be able, in the Finder, to select a set of files, perhaps with different file types such as Mellel, Papyrus, Pages and Keynote. A script would automatically calculate and remember the Path of each. It would then open each under it’s parent application, ‘print’ it as PDF and save it to my database, inserting into each file’s Info panel URL field the Path to the original file.