reciprocity factor and development

[Willie Jan]

Hi,
I read an old apx 100 pdf docment yesterday to see the reciprocity factor for it.

1sec +1F-stop -10% development
10sec +2F-stop -25% development
100sec +3F-stop -35% development

In the past I never heard of decrease the development when adjustments are made for the reciprocity factor. I always adjusted the shuttertime, but never the development.

Any comment about this here? Are you also decreasing the develop time?

 

[Ian Grant]

This used to be a common recommendation because the reciprocity affects the shadow areas in a greater proportion to the highlights so contrast tends to rise sharply, so it's better to compensate more in increased exposure and cut back on the development to hold the highlights.

Ian

 

[Lee L]

Because of the mechanism that causes reciprocity failure, traditional films tended to build additional contrast when exposed for the extended times involved. Shadow areas failed more rapidly that highlight areas. To compensate for this increase in contrast, decreased development was recommended.

This build up in contrast appears to be less of a problem with more modern films. See http://www.willwilson.com/articles/0403Bond_Reciprocity2.pdf for Howard Bond's excellent article and some comments on the five films he tested for reciprocity failure, some of which built little to no extra contrast at longer exposure times.

Lee

 

[Pinholemaster]

Expose for the shadows; develop for the highlights. The technology doesn't change, but people do get overwhelmed with the jargon such as "reciprocity failure" and the like.