Pyrocat HD & long exposures

[Bruce Osgood]

I've ordered my first batch of Pyrocat HD from Photographers Formulary, the liquid, and am mulling over the use of it when a question popped into my mind (It's after 2 am here).

Question: For those exposures longer than 1 second do you reduce development to maintain a N development? My feeling is that an 8 minute normal development would be reduced to 7 minutes for an exposure longer than 1 second and shorter than 5. For exposures longer than 5 seconds development would be even less.

I'm speaking of exposures AFTER film reciprocity and bellows extension have been applied where needed.

 

[Donald Miller]

I've ordered my first batch of Pyrocat HD from Photographers Formulary, the liquid, and am mulling over the use of it when a question popped into my mind (It's after 2 am here).

Question: For those exposures longer than 1 second do you reduce development to maintain a N development? My feeling is that an 8 minute normal development would be reduced to 7 minutes for an exposure longer than 1 second and shorter than 5. For exposures longer than 5 seconds development would be even less.

I'm speaking of exposures AFTER film reciprocity and bellows extension have been applied where needed.

Bruce,

Yes it is common practice to reduce developement to offset the increased contrast that reciprocity exposures induce.

As an example, if you photograph the interior of a building with only ambient outside light from a window included in the scene, the exposure required by the shadows may place you in reciprocity but the lit window values may be in normal exposure range...so when we add the additional exposure for reciprocity to expose the shadows properly we push the window values much higher then they are in reality. This increased contrast must be dealt with at the negative development or we will find that the highlights are blown out.