[LargeFormat] Pre-exposure in the real world

[Les Newcomer]

I didn't study under Ansel, so this may be a different, but certainly logical
version of what he was doing.

When the scene contrast is too high, slight variations in the shadows are
undectable, while higlights are off the chart.

By evenly exposing the film  to a 1 zone  'flash' you've doubled (or more) the
exposure in the shadows, increased midtones only slightly, and didn't effect
the highlights at all because they've already recieved too much anyhow.

This gives those deep, unprintable shadows a boost to where they are printable.

I didn't do it often, but when I did it, I did it after the fact. Interstitial
ions don't give a hoot when the get exposed.  And as long as you develop the
film "promptly" it won't make a difference if it's before or after, even a
couple of days after.

Notice too that anything more than a 1 zone boost on chromes will be noticable
since you won't have any true blacks, the shadows just look fogged.

I have heard that in his letters, he commented that he prefered (at least for
some things) uncoated lenses over the coated ones because they essentially did
this on their own.


Les


Bob Younger wrote:

> We did this for real, in the field, at the workshop with Ansel I attended in
> '79. It works just fine in the field. Use two pieces of opal (milky white)
> glass in front of the lens (large enough to cover the lens). Some folks had
> a spacer between the two pieces so that they could slide an ND filter in
> there if necessary. Determine what degree of pre-exposure you desire; meter
> through the glass (of course), and set your lens appropriately.
>
> Somewhere along the line I recall (perhaps incorrectly) some discussions
> about pre-exposure only being valuable (having an effect) for some finite
> amount of time following the pre-exposure. Don't recall if it was weeks,
> days or hours.....maybe others can add to this.......
>
> Bob Younger
> San Diego, CA
>
> ----- Original Message -----
> From: "Lee Carmichael" <click76112@charter.net>
> To: <largeformat@f32.net>
> Sent: Wednesday, January 02, 2002 8:02 AM
> Subject: Re: [LargeFormat] Pre-exposure in the real world
>
> > I, too, have read about this for many years.  I have never done it.  I
> have
> > always relied on the tried and true N-1 exposure or development to control
> > scene contrast.
> >
> > lee carmichael
> > click76112@charter.net
> >
> > ----- Original Message -----
> > From: "Cindy and Marco Milazzo" <mmilazz1@elp.rr.com>
> > To: <largeformat@f32.net>
> > Sent: Wednesday, January 02, 2002 9:10 AM
> > Subject: [LargeFormat] Pre-exposure in the real world
> >
> >
> > >
> > > I said I was full of questions about practical issues.  Here's my first
> > > one:
> > >
> > > In his books, Ansel Adams advocates pre-exposure as a way to control
> > > contrast and punch up the darker values. I've tried it, and it works,
> but
> > > it's somewhat dificult to accomplish in the field.
> > >
> > > Do any of you pre-expose, and if so, how do you do it? Are there any
> > > tricks or gadgets that help?
> > >
> > > TIA
> > >
> > > Marco --
>
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