Fog / strong vingette in film shots?

[MVA123]

Hi all

I'm developing some rolls. A few photos are affected by a small spot of fog in the center of the frame as well as some others having the exposure completely shift in the photo. Any thoughts on why/how this is happening? Thank you!!

 

[480sparky48 48]

The images aren't showing up.

 

[john.margetts]

Yes, no images.

It would be more helpful to post photographs of the negatives rather than positive scans as whet is happening outside the picture area is likely to be important.

A guess without seeing the pictures is that the film was touching itself in the developing reels.