[Alex1994]

Hello

I want to take a long-exposure photo during the day. Here's the question: how do I get an exposure of, say, 20 seconds at 100ISO without having a ridiculously overexposed photograph? Narrow aperture like f/22 is a good idea, anything else needed? Any general tips on long exposures?

As usual I'll be using film, I have heard about this thing called reciprocity failure, if anyone could explain it I'd be very grateful.

All help much appreciated

Alex