Pre Exposure

Do any of you pre expose film to a neutral subject on Zone I or II to raise shadows in an image? What are you experiences and advice to those who want to try it.

flash19901 said:

Do any of you pre expose film to a neutral subject on Zone I or II to raise shadows in an image? What are you experiences and advice to those who want to try it.

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I use this in extreme SBR situations. I don't expose to a neutral subject perferrring instead to pre-expose through an sheet of opaque acrylic.

I have pre-exposed as high as one stop less then meter indications,(I suppose that for Zone system practitioners this would be Zone IV), depending on the SBR of the scene.

The second exposure works best if the exposure is placed at three stops more then meter indications. (For Zone Sytem users this would be Zone VIII).

This method gives shadow elevation without the runaway high values that Ansel Adams method can produce. (Adams used low value determination for both exposures).

It is a process that should be used in certain situations...not all situations

I'm with Mr. Miller. Pre-exposing in the field CAN be useful, but post exposure in the darkroom is usally better.

When you find pre-exposure more than an unusual thing, you might think of switching films.

Interesting enough, the higher luminance scenes tend to have a higher flare factor which acts like pre exposure. This is something Adams never mentions. In these conditions, there is a built in pre exposure; however, there are conditions of normal flare with high luminance scenes.

The concept of pre exposure is also a good example of the influence of flare on film speed.

For what it's worth, I personally try not to use pre exposure because for the compression of the local shadow contrast.