c-41 black blotches

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Wayne

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I haven't done a lot of C-41 processing so I'm still a NOOb to this particular process, and my last 2 batches of 4x5's came out with a LOT of tiny irregular black blotches in the emulsion on some but not so much on others. I looked at them under a dissecting scope and they seem to be at the same level as the image, not above or below. I assume its just dust spots but thought it worth checking to see if there are other C-41 errors that could cause this. I loaded these holders in the desert and shot some of them there and they might have attracted a lot of static particles, or maybe I wasn't careful with my lens cleaning. Whatever it is, I've never seen dust spots so numerous before on black and white or transparency film and I've shot in the desert plenty of times before.
 

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Dust would create clear orange spots of unexposed film.

This is either poor bleaching and fixing or chemical contamination or some third event that is less obvious.

PE
 
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Wayne

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Hmm... well it is a blix kit, Unicolor to be exact. I mixed the developer and blix fresh. I always run the blix a bit longer than required. Its possible the blix was warmer than the developer by a few degrees but not more than a few. The stabilizer had been sitting a while (months) but was barely used. Can't imagine that had anything to do with it though. The blotches look like little roundish but irregular clumps of something deep in the emulsions...

Maybe my water? Same water I've always used too. It is filtered well water but I suppose mineral content could vary
 
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Wayne

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I checked my HF-360 filter and it is showing some reddish sediment in the clear filter housing.

Is there a filter cartridge that effectively removes all the iron or is bottled water for dev/blix the only way to go?
 
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Wayne

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I only use distilled water for processing. At .99 cents a gallon I think it is a no-brainer.

Nobody has ever accused me of having a brain. To wit...

I tossed my previous batch and ordered a new kit. I mixed up the developer with distilled water, then topped it off. With tap water. The same tap water as before.

ARRRGGGGGGGGGGGGGGGGG. I can't believe I did that.

I wonder if there is any way to de-ironize it now that its mixed. At least it shouldn't be as bad as before because it's mostly distilled...
 
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Wayne

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But you don't have black blotches on your negs...
 
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Wayne

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I was going with the iron theory...I already use filtered water. Fortunately I mixed the blix with 100% distilled water so if it does happen again I can (perhaps) narrow it down to iron in the developer?



See posts 2 and 4. I use filtered tap water!

Works fine.
 
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