If you rely on a bad PDF, you will miss critical annotations. Van Perlo wrote long, humorous footnotes. In one, he says: "My opponent here offered a draw. I laughed. He had forgotten the knight check on e4 that I had been dreaming about for ten moves." A scanned PDF might cut that off.
To get the most out of the Van Perlo 39 Endgames Tactics PDF, consider the following study tips: van perlo 39-s endgame tactics pdf
If you are referencing a specific game or diagram (e.g., Diagram 39S or position 39 from a database), it likely illustrates the superiority of the Rook over a Knight in specific strategic situations, or the coordination of Rook + Bishop/Knight. If you rely on a bad PDF, you will miss critical annotations