Strange "comet shape" over-developed streak with prescysol... any idea?

[Vania]

Hello,

I've been using Peter Hogan's Prescysol, semi-stand method, for a while now, and with much satisfaction since I switch from filtered water to demineralized water.
But coming back from a photo trip, my first 2 rolls of 120 films gave me weird overdeveloped streaks in the highlights (namely sky area) on some frames. Quite fortunately, the good ones have been spared! Nonetheless, this is quite important work to me, and I can't afford to take any risks with the rest of my film batch.
So I need to figure out precisely what is causing this, and if I can safely keep using Prescysol (which I was really counting on) for the rest of the job.

The film is tri-x. I use the standard semi-stand process @ 24°C for 10'30 with a 5 min presoak in demineralized water.
I rinse for 2 min in running water (I change the water 3 times with about 6 to 8 inversion each time).
I always use the same fixer with Prescysol, Berfix 2, made by Bergger specifically for pyro development, and fix for 5 min. I reuse the fixer only once (which was the case here) and add 1 min. Fixer is diluted in demineralized water.
Final rinse is 20 min, then I leave the film for 5 min in demineralized water so I don't need to use a wetting agent.

Any help trying to understand what is going on would be much appreciated, as I am totally clueless... (hope Peter Hogan is around!)
Following are some scans of the problem at hand.

Thank you all for your help.
Vania

 

[Tom Kershaw]

What film did you use?

Tom

 

[Vania]

Tri-x

 

[JPD]

Undissolved particles/crystals in the developer stuck to the emulsion. It looks like a comet around them because the developer becomes much more concentrated around the particles, and gravity forces it downwards when it slowly dissolves due to the agitation.

 

[lxdude]

Quick, send it to the National Enquirer and say it appeared over Area 51!

 

[Vania]

Undissolved particles/crystals in the developer stuck to the emulsion. It looks like a comet around them because the developer becomes much more concentrated around the particles, and gravity forces it downwards when it slowly dissolves due to the agitation.

Thanks Patric! This is very informative. Unfortunately it looks like bad news for me... I absolutely love this developer but I can't afford to take any risk with these films. What surprise me, is that I always check the developer for residue before pouring it in the tank. Those crystals must be impossible to spot.
Is this a common trouble ? any tricks to make sure it doesn't happend again ?

 

[nhemann]

I work with caffenol a lot and I always run it through a coffee filter (no pun intended) to keep any clumps out - could you do the same?

 

[Steve Smith]

Shake the B bottle before you use it. If it rattles then some of the solution has crystalised. It can be warmed up in a microwave and shaken a bit to dissolve the crystals back into the solution.

Instructions (which I'm sure you have already): http://www.monochromephotography.com/section255920_83798.html

NOTE: because solution B is a saturated solution, at low temperatures it may crystallize to form a sediment at the bottom of the bottle. Warming the solution, in either a water bath or a quick zap in a microwave, will return the crystals to solution. This will not affect the developing properties. Using a partially-crystallized solution will result in under-developed negatives.

Steve.

 

[Vania]

Shake the B bottle before you use it. If it rattles then some of the solution has crystalised. It can be warmed up in a microwave and shaken a bit to dissolve the crystals back into the solution.

Thanks Steve. I do shake the bottle before use, a lot actually, an I also heat it up if I hear any noise. The coffee filter sounds like a good idea though. I should try to ask M. Hogan if it's a sound thing to do.

I just checked the B bottle and there is some crystal residue on the bottle itself. Maybe some of it fell in the developer and could not disolve... sounds a little paranoid, but it might be the case...

 

[Ian Grant]

Unfortunately this developer is sold with a Part B Sodium Carbonate solution, it's more normal for commercial liquid developers to use Potassium Carbonate because of it's far better solubility.

Ian

 

[Vania]

I just got an answer from Peter Hogan (the maker of the developer) on the same post in the FADU forum. He suggests that the culprit might be the film emultion. Even if I find it surprising, I must say that in about a year of regular processing with Prescysol, this problem occurred only once.

I've spent some time examining these negs, and I can't think of any processing problem whatsoever that would result in such identical marks repeated like this. I've never seen this with any developer, let alone Prescysol! I would say it is almost certainly a fault with the film emulsion, and I would suggest sending them to Kodak for their opinion. Carry on developing, Vania!

 

[Ian Grant]

Vania, it's definitely not a film fault, it's happened during processing, and specifically the development.

I've seen slightly similar occur with films where there's been fixer contamination caused by dirty dev tanks (a college darkroom), in that case dried fixer crystals lodged on the film, you get the same comet shape but a dark spot on the print where the hypo crystals acted on the film.

You should also check part A just in case there's some crystallisation there.

Ian