Quote Originally Posted by Thomas Bertilsson View Post
You got advice to use distilled water by Ian Grant. Did you take that step?
No I didn't (blush on face). I used tap water with the developer, stop and fixer (all fresh from the manufacturer's bottles). Washing was also with tap water. Only the final rinse was done in distilled water, with a little wetting agent added.

Because the marks on the negs are along the negative I figured they would come to exist during the drying process, not during any of the previous steps, which have no 'vertical orientation bias'. But then, like Ian said, there may be small particles of iron in the tap water that react with my fixer and thus bleach the film before drying.

If the latter is true then it still seems odd that the marks have such a definite orientation along the film. That simply doesn't make sense.