lines of black spots on HP5 negative

[s800]

Here's one I've never experienced before.

Vertical lines of small, well defined spots on an HP5 negative (4x5). See attached, this is my first time using Pyrocat-HD, but the 3 other negs from this batch aren't showing this.

Almost an inch long ... two groups.

Any thoughts?

Really appreciate input on this. Thank you.

(image inverted from neg)

[s800]

here's the zoom in
253506

[Steven Ruttenberg]

Looks like contamination. Perhaps while the film was drying. Did you use Photoflo or similar? Looks like little soap bubbles dried on the film. Have you tried washing the film in distilled water?