i was talking to someone today - don't want to call him an 'olde timer', but he is much older than me and ... :)
he was telling me all about flashing film before you expose it.
he suggested that one could pre-flash film - close down about 5 stops, out of focus / neutral gray or overcast north sky - and then expose "normally"
you will get more details in the negative when you make your actual exposure.
it doesn't work on every subject, but it will bring out details that would be not captured if the pre-flash was not done.
i know there are people that have done all sorts of things here, anyone actively do this, or at least tried it?