Quote Originally Posted by summicron1 View Post
There's no way your camera caused fogging like that down the middle of a lengthwise piece of film. Has to be fogging from some other cause.
Correct me if I am wrong, but the examples posted by the OP are positives, so if there is any fogging, it is at the edge of the negatives, not the centre.

It looks to me like something is in the light path near the centre of the image field.