electric arc

[Photo-gear]

I suppose an electric spark took place when I removed the cassette from the camera. I heard a noisy snap when the film was taken off.

It's only once the film was developped and scanned that I realized that 3 exposures had a single white curby line, that I started considering it was an electrical arc.

I don't believe it is a bromide formation.

Film: an old Ilford FP4+ shot at speed box.
Camera: Nikon L35AF
Developper: HC-110 dilution G (1-119) 60 min at 20C
semi-stand dev.: 3 inversions every 20 min.
Steel tank.

Click to enlarge the first picture. The white curb line is encircled.

 

[Mike Wilde]

yes, low hunidity, and the action of winding (or more often, rewinding) film into the cassette can cuase this to happen. I think that major vendor cassettes have the felt light trap trweated with anti-static measures to discourage this.