Odd unexposed area?

[joshyface]

Earlier in the year, when I looked at my roll of newly developed film, there was a spot on the corner of one of my negatives. It kinda looks like what happens when film is touching and part of it does not get exposed to the chemicals, but it's only on this one negative (near the middle of the roll). I am wondering what could have caused it, or if anyone has experienced anything similar.

Anyway, I developed the photo... and then solarized it. Here it is:

 

[timor]

A good subject for solarization. Did you solarized print or film ?
This spot, is it extending to another frame ? Or is it sharply cut on the edge of the frame ?