Donald Qualls
Subscriber
when that light impinges upon a frame of the film that has been exposed in camara, that part of the film will have received the extra exposure from the pinhole which may now reveal itself as an area of greater density when developed.
This is the idea behind "preflash" -- but it wouldn't be visible in the level of density in the example negative up thread; preflash (correctly done, below Zone I exposure level) will push Zone I up to Zone II, approximately, but won't add enough exposure to push Zone II into Zone III. The area that shows those density bars is around a Zone III to IV, to my eye.