Quote Originally Posted by wburgess View Post
......Having looked at the same FP4 Plus rolls, the 120 backing is clear whilst the 35 is slightly purple/blue. Why would this be different, surely it's the same formulation?

Would over/under exposing cause much difference in contrast and tone range?
The film bases are different. 35mm film base in most cases has density built into the base itself. In the case of 120 film, antihalation is dealt with by with a back coating which washes off during processing. This is not a problem.

Underexposing will result in conspicuous clear shadows (in the neg) and general lower density. In prints it will result in somewhat dark featureless shadows.