Quote Originally Posted by MattKing View Post
Although we tend to think in terms of longer shutter speeds when we consider reciprocity failure, the actual cause for that type of reciprocity failure is that the light that actually reaches the film is at a very low intensity. If you can increase the intensity of the light reaching the film, by using either more light on the scene or a larger aperture, the reciprocity may not fail.
Exactly Matt, I believe..

This was in a factory, with probably 40' ceilings or higher. Very dark in there relative to shooting near an open door, which I didn't have access too.

Good learning experience for me. I've heard of Reciprocity Failure, but never could get my head around it.