Incident meter(Negative film) Bright Light: Close down 'one stop' if metering is based on 'shadow' and open up 'one stop' if metering is based on 'hightlight', provided that scene has both shadows and highlights.

Diffused Light: Just incident meter the scene. If not, adjust after testing.

Incident meter(Slide film): Just incident meter the scene since its range is 5 stops.