I would use the term "purity" when talking about a copy of a master. And a studio would not lend out a master tape; they would send a submaster or a clone. If someone is telling you he has a master, it's most likely going to be an exact duplicate (clone). Anyway, nowadays master tape is being transferred to digital files.
But we need to be specific; are we including analogue tapes that have been remastered to digital?
With digital masters (which are files), a studio can burn a copy, that in theory, is the same quality of the master.
So with a master tape, you are hearing the purity of the sound on the tape, however, at a show where music is being demoed, the coloration's of the system and the room will never match the original studio.
But we need to be specific; are we including analogue tapes that have been remastered to digital?
With digital masters (which are files), a studio can burn a copy, that in theory, is the same quality of the master.
So with a master tape, you are hearing the purity of the sound on the tape, however, at a show where music is being demoed, the coloration's of the system and the room will never match the original studio.