How grainy can it get?

I had an old, expired roll of Fuji NPS 160 (expired in 2002!) in my
Kodak Retina 1a camera for more than six months when I finally
finished it and got it developed this week. When I put it in the
camera I knew it was the 160 film, so I was shooting it at 80 or so,
and getting pretty good exposures. But by the time I was half-way
through the roll, I forgot what film it was, and thought it was a
fairly recent roll of Fuji 400, so I was shooting it at something
around ISO 300. That stop-and-a-half difference made a big difference
in the exposure. This shot, for instance, was very much
under-exposed.

But R has such a sweet smile that the picture's not bad anyway. (I
did quite a bit of stuff -- dusting, burning, dodging, de-saturating,
etc. -- to this picture to get the best from a very bad negative.)