Cause of black specks on negative...?

Hello. Scratching my head over the cause of the regular pattern of black specks on the negative which is associated with the attached image (zoom in to see what I mean). The film is Acros and it was processed by a local Winnipeg photo outlet. The other film submitted at the same time was HP5 and it came back fine. Has anyone any suggestions as to what might cause this effect?

Thank you in advance.
jim

I think I see black specks on the positive which would imply white=clear specks on the negative. Dust on the negative at the time of exposure can do that. A magnifier on the neg should show the problem. If not it's a problem somewhere beyond the neg.

Maris said:

I think I see black specks on the positive which would imply white=clear specks on the negative. Dust on the negative at the time of exposure can do that. A magnifier on the neg should show the problem. If not it's a problem somewhere beyond the neg.

Click to expand...

Thank you for the reply. I thought dust or traces of undissolved chemicals from development. I rewashed the negs and rescanned and the specks are still there. I don't know. Maybe a flawed emulsion mix and/or some developer contamination. As I said, the HP5 was clean and scanned well....?