This is not quite correct... For motion picture film, yes, anything older than the 70mm film you're talking about tends to be low-resolution because of the phys

This is not quite correct... For motion picture film, yes, anything older than the 70mm film you're talking about tends to be low-resolution because of the physical constraints of moving a foot or more of film through a camera each second. However, still photos from that era were much better - the limitations of film stocks were lighting, and with enough light to gather, a large format photo could be extremely sharp and high-resolution (if that was the priority). It sounds like this is referring to a formal portrait setting, with potentially very bright studio lighting and high quality film, so it could easily be sharper than all but very recent digital cameras (as large-format film still is).