Foma Retro320's odd result

[MsLing]

IDK why these two sheets are so horrible. The scan looks so dirty. I don't know why such a flare was on the underside. Beside, its original image display thick B+F. It's sure that these sheets were always kept in dry and cool shelf and they must be fresh enough. Also, I've checked all my empty film holder, fine they are. So where that flare and fog came from?



Here is the " original" scan( only invert it). Awful. Sorry I didn't export the neg.

 

[koraks]

Could you post a some photos of the actual sheet of film, viewed on a light table, please? So not scanned or inverted, but simply photographed e.g. with a phone. This will help nail down the problem.

My first thought is that it might be insufficient fixing.

 

[MsLing]

Could you post a some photos of the actual sheet of film, viewed on a light table, please? So not scanned or inverted, but simply photographed e.g. with a phone. This will help nail down the problem.

My first thought is that it might be insufficient fixing.

OK. I will fix it again to confirm.

 

[MsLing]

I've fixed it again in another fixer 10 more minutes. Disappointedly, nothing has changed. Instead of silver halide, fog and marks seem more like silver.

 

[koraks]

Thanks for uploading the photo. There's indeed massive fog on that sheet. There can be many causes for this:
1. Storing or handling unprocessed film in incomplete darkness, i.e. during loading the film into holders and also while processing/developing it.
2. Light leaks in the camera; this is excluded in your case since the edges of the film are also fogged.
3. Light leaks in the film holder; I don't think this is likely due to the pattern of the fog.
4. Dichroic fog caused by influence of chemicals; especially sulfur-based compounds; this can occur during storage or processing.
5. Incomplete fixing followed by reduction of silver halide into metallic silver, e.g. due to 'printing out' by UV light or daylight or by chemical means (e.g.developer carry-over).

I might be forgetting possibilities.
#1 is by far the most common cause.

 

[MsLing]

Thanks koraks. I'll check all these, especially my changing bag. I just switched to using reel for developing. So I should check the connection between core tube and lid. A few sheets will be victimized

 

[koraks]

changing bag

Changing bags can be tricky. The one I have has double pairs of elastic bands around the sleeves, and I found that when they slid too close to each other, they would not always create a lightproof seal around my arms. Another concern is the zipper; this is generally not light-proof and relies on it being covered with a flap of material. I also always opted to place the bag with the zipper facing down.

I just switched to using reel for developing. So I should check the connection between core tube and lid.

Oh yeah, that's one other potential cause of light leaks: an incomplete light trap on the development tank. Something simple like forgetting to mount the center column will result in fogging.

 

[snusmumriken]

You don't mention how you developed this. I just wondered whether it could be silver chemically re-deposited during development? I think that's an addition to @koraks list above.

If that's the cause, the affected areas would have an obvious sheen when viewed at an angle under a light, from the emulsion side.

 

[koraks]

I think that's an addition to @koraks list above.

Yes, in fact it's something I'd consider part of the complex hiding behind #4. It's rare for this to occur in my experience; the only time I've had this was with Shanghai film from a box that had been opened about a year earlier. All subsequent sheets from that box showed severe dichroic fog for a reason I still don't quite understand. I suspect it might have been an interaction between the film and its packaging materials.

 

[MsLing]

If that's the cause, the affected areas would have an obvious sheen when viewed at an angle under a light, from the emulsion side.

Thanks for the suggestion. Hmmm, at least I cannot observe dichroic fog on the sheet.

You don't mention how you developed this.

I used Rodinal 1+100, 24℃, 65min. And I shake the tank about 10sec every 5min. IIRC, Rodinal doesn't contain strong silver halide solvents, so it's not easy to create dichroic fog.

As for chemical pollution, the beaker which I use to mix developer is special, and I use distilled water. That's why IMO, developer can hardly be polluted by other chemicals like hyposulfite.