Blotchy film

[darinwc]

I developer a couple of rolls of Fomapan 200 in Ilford DDX.
It looks great except in the skies where I get strange blotchy patches.
Is this more likely the film or development or...?

 

[koraks]

I bet you're shooting this film in 120 format. That's not a really good idea if you're looking for clean negatives, since the film is inherently problematic in this format in particular (35mm and sheet film are fine) and the problems have been with it for decades now.

I see two distinct issues on this section:

Cyan/blue: typical 'zits' found on Foma 200 120 format - this film and this format specifically. It's kind of unique.
Red: 'blobs' that are likely backing paper offset issues; this is specific to film that's interleaved with a backing paper (i.e. 120 film), but not unique to Foma 200. The problem is generally exacerbated by too long storage (expired film) and/or high heat or moisture getting to the film during storage. 120 film is best used fresh, stored reasonably cool and dry (especially after it's taken out of its foil wrapper!) and processed shortly after exposing it.

 

[darinwc]

Thanks for the info! I got a brick of the Foma for cheap and now I know why. I'll try a different film with my current setup and see how it goes.

 

[koraks]

Yeah, this might be the explanation, although some people have used this film and noticed no defects. However, at the same time, many people run into it sooner or later, and to a larger or lesser extent. I recall my initial rolls went fine but within 3-5 rolls I ran into the problem marked in blue in virtually all frames. Foma graciously replaced my film, but the replacement film suffered from the same problem. I gave up on it at that point, but still (happily!) use the same film in sheet formats, which I like very much and has always been problem-free for me.

Just to check - you can confirm this is the 120 product that you were using, yes?

 

[darinwc]

Yes this is 2 rolls of 120. I still have I think 8 more rolls I can at least use to test cameras. But I want to rest with another film before I conclude is is the Foma film.

 

[koraks]

Okay, thanks. The defect circled in blue is definitely a Foma-specific issue. The mottling occurs on virtually any brand of film under adverse conditions and it's not something Foma-specific, however, it's still fairly rare in reasonably fresh (unexpired or recently expired) film.

 

[thinkbrown]

I haven't done this enough to be certain it's not just roll to roll variation, but when I've got a wonky roll of foma 200, an extended prewash seems to reduce the issues. I don't normally prewash film, but the last few rolls of my brick of foma 200 I subjected to a ~30min prewash with a change after the first 10min and it seemed to help reduce some of the mottling and streaking.

It's a pity that foma's QC just isn't that great on 120 because it's pretty stuff.