Why are there little white dots on my bw negative, and how can I fix it?

Question

I've been deving some bw film at home, but on one of my negatives there are a lot of little white spots everywhere.

Why has this happened, how can I prevent it from happening again, and how can I fix it?

My scanner does not have a clean option, so it's probably fix one by one in photoshop.

Thank you! Any advice is much appreciated.

Answer 1

It's been many years since I've done film developing, but I remember two likely culprits:

1. Air bubbles from improper agitation. Generally these are very roundish.

2. Minerals from hard water. These tend to be angular shapes.

Answer 2

Since you note:

they dry next to a window which could have been left open for this set of negatives

As Hueco explains (1, 2):

Looks like dust. How clean is your dev environment from the change bag through to the drying rack? Specifically with drying, is it done in a clean place with no airflow or only cleaned airflow?

Windows are always drafty. If you have no dedicated place, then try using a seldom used closet and, once hung up, make sure not to open the door for ~a day. Make sure any AC/Heating vents in the room are also closed. No airflow is better than non-filtered air.