Anyone else familiar with a book by W.F. Berg, Exposure Theory & Practice. I'm reading through it and have come across a section on RF where he gets into the technical aspects of its effects on film grain. Part of the discussion is about the surface image and internal image on the film grains, this is a concept I was not aware of, can someone simply explain the surface and internal images, what they are and how they work?

This discussion on RF is addressed in terms of low intensity and high intensity exposures, and how both are handled by fast and slow speed films, as well as b&w, c-41 and e-6 films. Without going deep into the specifics the chemical response of film grain to long and short exposures as described in the book, there is a reaction that creates a surface image and an internal image. If I have grasped this correctly the surface image disappears early in development and the internal image is set in the next phase of chemical reaction.

While the book is quite technical and stretches my thinking, I'm enjoying the challenge of going into uncharted and possibly superfluous areas of photographic understanding, particularly around exposure and development concepts.



Cheers