Some strange low-density spots on my film

MsLing

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I just switched to PSI version Xtol, and developed two rolls of Foma200 film in a week. Unfortunately, however, some low-density spots randomly spread on images. I use fridge to cool Xtol stock to 20℃ before processing. The first roll was processed with very fresh developer, which I dissolved 10-20 min before developed the film. When saw those awful negs, I doubted that maybe my developer was so fresh that some undissolved particles still exist. So I wait for days and processed another roll, then got the same result.



If reverse any image which with spots, dark "cores" can be seen in the center of each spot. Seems like some solid things, for example, KBr, sticked on emulsion and inhibited AgX's reduction.

 

Sirius Glass

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Are you filling to the top of the tank?
 

retina_restoration

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It is becoming widely acknowledged that Fomapan 200 (some batches) have a problem that requires an unusually lengthy water pre-soak. Blue Moon Camera advises customers to presoak the Foma 200 speed film for at least twenty minutes before pouring in the developer, to eliminate problems. (They also recommend a final wash of 20-30 minutes) I suggest you try this next time.
 
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MsLing

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Sirius Glass said:
Are you filling to the top of the tank?
Click to expand...

Yes

Well, an hour before I mixed this bag of Xtol, I used my old Xtol to develop another Foma200 and that roll was Okay, except really low density(Dmax about 0.95D). I usually buy foma's 35mm bulk film, and all negatives I showed are from the same 50m roll. I've never saw such a result in this roll with any developer.


I am going to filtrate Xtol and try one more roll tomorrow.
 

Sirius Glass

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I have not see your situation before. Usually if the tank is not filled enough it is across all or most of the negatives.
 

koraks

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Those look like air bubbles to me, clinging to the film early on in the development process. More vigorous agitation in the first 30 seconds of development may solve this.
 

Sirius Glass

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koraks said:
Those look like air bubbles to me, clinging to the film early on in the development process. More vigorous agitation in the first 30 seconds of development may solve this.
Click to expand...

Also few quick hard thumps of the bottom tank will take care of that problem right a the start of processing. I do that on a hard rubber block instead of the counter.
 
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MsLing

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koraks said:
Those look like air bubbles to me, clinging to the film early on in the development process. More vigorous agitation in the first 30 seconds of development may solve this.
Click to expand...

I follow Kodak's guidance, always continually agitate 30s after pour in developer. And hit tank for 4-5 times after agitation. I never see any air bubbles before. And IMO, a typical air bubble would only lead to a simple spot.
 

John Wiegerink

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If you look at the "spots" on the negatives the OP has posted you'll see a tiny dot in the middle of almost all the lighter density circles. Almost like maybe a teeny-tiny speck of one of the chemicals in the developer lodged itself on the soft emulsion and disrupted development in that area. I know all about Foma 200's reputation for defects and have seen it first hand myself with their 120 film version, but use Foma 200 in bulk 35mm with no problem.
 

koraks

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John Wiegerink said:
If you look at the "spots" on the negatives the OP has posted you'll see a tiny dot in the middle of almost all the lighter density circles.
Click to expand...

Good catch, I hadn't noticed that before. This doesn't look like air bubbles.

Try what @retina_restoration said and rinse the film before developing; see if that makes a difference. My best guess would be some particulate contamination that sticks to the emulsion and locally reduces development. I'd try two things:
1: Try a different developer with this film and see if the problem doesn't occur.
2: Try this developer with a different film.
At this point it's not clear to me if this is indeed particulate contamination and if so, where it originates. So try a process of elimination.
 

250swb

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I've had spots like this with a few rolls of CMS20, a halo surrounding a dark spot, and they only ever appeared in the first three or four frames, and usually only in areas of even tone such as the sky. But it's a very different film from Foma 200 and I was using Adotech developer, so there's no correlation. Never found out what caused it but definitely not a lack of agitation or not filling the tank properly. My only theory is some sort of contamination during the manufacturing process given the rest of a 36 exposure roll would be fine, but why did they only appear in the sky?
 
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