Well, here is the more egregious example taken on Kodak Ektar film, 100% scan:
It highlights the two problems I'm often facing. First, Ektar base is very soft and I often get fine scratches. It does not happen as much with Fuji films. But the most annoying problem is the drying spots from the final rinse. These spots are rather exaggerated by the film scanner, with optical printing they are less noticeable, but they are still there.
This roll was run in all Kodak's flexicolor chemicals mixed in distilled water, final wash and final rinse are both distilled water. Jobo CPE-2 processor. I washed the tank prior to use, and drying is done in a clean drying enclosure.
It appears that the spots are almost always on the back side of the film. My current theory is that these are additives in the final rinse that are left over after water dries off.
Here's what I tried so far:
I tried adding a bit of photo-flo and/or 91% rubbing alcohol to the final rinse without improvement in the results.
I tried diluting final rinse without improvement in the results.
I tried filtering final rinse through fine metal coffee filter prior to use without noticeable improvement.
I tried wiping the film back with my fingers dipped in final rinse after hanging it. More scratches and no improvement in the results.
I tried wiping the film back with squeegee. Too many scratches, won't do it again.
I tried wiping the film back with a kitchen sponge dipped in final rinse. I get a few perfectly clean frames and a few frames with huge drying spots.
I tried drying film horizontally curled in a spiral. Results are better, but still a few drying spots can be found, usually at the lower edge of the film.
I tried getting final rinse off of the film before hanging by spinning it in a salad spinner prior to hanging in a drying enclosure. Results varied from slightly better to dramatically worse.
I tried drying film in a shower after running hot water for a few minutes. No improvements.
I tried three-step wash process: first tank of distilled water with a drop of Photo-flo followed by several tanks of distilled water until there is no more foam. I can reduce number of big particles that way, but drying spots still show up.
The best results I got so far is when I use a bit of Photo-Flo and rubbing alcohol in distilled water instead of the final rinse, hang the film in the shower and then pour the remains of Photo-flo on the hanging film from top to bottom. But, PE said that not using final rinse is not a good idea, so the search is still on...
So, any more suggestions?