Pre and Post Exposure Question

I have heard about using either a pre or post exposure with color film to control contrast. I would like to try it.

Has anyone here done this? I need techanical info.

(Note: I do 4x5 view camera, both positive and negitive color film, I have a Pentax Spotmeter V exposure meter)

Thanks

I have pre-exposed slide film to control contrast, it work well enough. You simply aim it, out of focus, at something uniform and featureless (e.g. the sky, some concrete, a piece of paper) and expose it 3 stops faster than your main exposure will be.

There is a calibrating gizmo (expodisc), normally used for white-balance control, but you can put one on your lens and preflash with it as well:

Dead Link Removed

(You could make yourself an expodisc out of something translucent)

You could also preflash your slide film in the darkroom.

I never tried preflashing c41 films, since they have so much range anyway. If I really expected problems with contrast I'd simply rate the film at box speed or a wee bit faster, and/or use a graduated neutral density filter, etc....

hi christopher

to build upon what keith suggested ..

(there was a url link here which no longer exists)

it has been years since i posted that thread
and i haven't done it yet

good luck!

john

Thanks guys for the info..
the APUG forum posts did the trick...