If you had ever bothered to look, you would have found that what you speak of is properly called reciprocity law failure and it is a result of either very low light levels at one end, or very short exposure times at the other end. It is not a suggestion. All of the questions you ask above can be answered by a short study of sensitometry. Read up on it, like I did. http://www.amazon.com/Photographic-S.../dp/0871001802
Bookmarks