Unregular stripes at the frame edges

[Donald Qualls]

I've never seen marks like that on my negatives, and prior to this past weekend, I've inverted that way every time I've processed either B&W or color. The only time I've ever given really vigorous agitation was when using Super Soup to get EI 5000-6400 out of Tri-X. Most recently, for C-41 I've tried agitation with the "stir stick" that comes with Paterson tanks. Paterson apparently recommends that only for the first agitation after filling, so you can start agitation without waiting to seat the inversion cap -- a delay I haven't see cause problems -- but back when I learned to process film plastic tanks couldn't be inverted without pouring out the contents, and all agitation in those was doing by "twirling". In my experience, it works fine.

Of course, a light leak in the tank funnel could also produce slightly lighter lines that match the spacing of the film reel spokes. Here's a possible test (if you're willing to sacrifice a roll or, with 35mm, a partial roll of film): load unexposed film into the tank normally, and then let it sit, in the light, with the inversion cap off, for a good while -- even take it out in the sunlight. Once you've given it some time to fog really well if it's going to, develop the film inside without opening the tank.

If it's fogging due to (for instance) a not-quite-opaque tank funnel (which I've heard of), this will show similar marks even though the film is unexposed. If it does, you'll know you're getting light either past or through the tank funnel. If not, then you'll have eliminated a light leak in the tank as a cause and we can try to figure out what's happening to your chemistry to make it do this.

 

[Centurio]

I've never seen marks like that on my negatives, and prior to this past weekend, I've inverted that way every time I've processed either B&W or color. The only time I've ever given really vigorous agitation was when using Super Soup to get EI 5000-6400 out of Tri-X. Most recently, for C-41 I've tried agitation with the "stir stick" that comes with Paterson tanks. Paterson apparently recommends that only for the first agitation after filling, so you can start agitation without waiting to seat the inversion cap -- a delay I haven't see cause problems -- but back when I learned to process film plastic tanks couldn't be inverted without pouring out the contents, and all agitation in those was doing by "twirling". In my experience, it works fine.

That is very interesting and seems a real option when I finally detected this error. I would really like the idea to just twirl the film with that stir stick in the paterson tank instead of shaking or flipping the box constantly. Would make it much easier. I just was afraid that the chemistry won't mix properly so I let go of this idea ... How often do you twirl the films? Once for around 5 seconds every 30 seconds I guess?

Of course, a light leak in the tank funnel could also produce slightly lighter lines that match the spacing of the film reel spokes.

Pretty sure that this is excluded since the issue occurs only developing in c-41. Never seen an effect like this on my b&w negatives I was developing in the same tank ...

I have another guess that I really hardly accept: The developer itself. I have no real explanation for that presumption but it seems like it could be the last remaining possibility. I use a Compard Digibase C-41 developer. Beginners say, it works really fine, experts say (what I heard) it's a crap. Well, I don't know, but I'm really willing to test another one. Maybe the classic Tetenal.
What do you think about it?!

 

[Donald Qualls]

I treat one good long back-and-forth twirl with thumb and finger as equivalent to an inversion, and gave five such agitations in a 10-12 second period each minute. Actual Kodak recommendation (for the chemistry I have in "small tanks") is to agitate continuously first 30 seconds, then ten seconds agitation every thirty seconds. I'll probably try that next time I process color.

I don't think there's any question that inversion is more effective agitation than twirling, but I'm trying to limit the amount of air introduced into the developer -- see below.

I know nothing about the Compard, never tried the Tetenal (though I keep seeing it recommended). First time I processed C-41 (2005-2007) I started with Flexicolor and then switched to a home-mixed 2-bath C-41 developer. During my recent restart, I used a Cinestill Cs41 kit until it died (which I quite liked and still have a backup dry powder kit for), and after it expired I went ahead and sprang for actual Kodak Flexicolor chemicals -- Developer/Replenisher, Developer Starter, Bleach Replenisher (used without starter) and Fixer/Replenisher (also without starter). I prefer a separate bleach anyway; the bleach and fixer both last better when separate, and I have the option to do bleach bypass any time I like. I'm using a Final Rinse left over from my first go at color, also have a small bottle that came with my Cinestill kit; modern films don't need a stabilizer. The other potential advantage of the Flexicolor is that the developer can be replenished (which I've been doing with my Xtol for a couple months now, though for C-41 chemistry this is experimental). Replenishment, if it'll work on our scale, is easily the most economical way to process film -- and I'll know in a few weeks whether the developer holds strength or starts to deteriorate.

Not sure what availability is in your part of Europe, but Tetenal is manufactured and packaged in Germany, so likely available. From what you're saying, it really does sound like the developer may be the issue. I think you said this was the first roll in freshly mixed chemistry?

 

[Centurio]

As far as I know, the chemicals you were talking about are not commonly available here. I'm living in Germany. So, you mentioned it, Tetenal is very commonly gettable and I think I should give it a try.

I think you said this was the first roll in freshly mixed chemistry?

Right! The developer was freshly mixed but the stock solution was not totaly fresh. I'm pretty sure that it was still good because all single parts had the right "color", which should be transparent. But I'm pretty sure that it occured also with absolutely fresh stock solution. So I'll just want to have a try with Tetenal ...

 

[Donald Qualls]

So I'll just want to have a try with Tetenal ...

That seems like a sensible way to eliminate the developer as a factor.

 

[Centurio]

That seems like a sensible way to eliminate the developer as a factor.

I guess so! I'll keep you up to date as soon as I have some results.

Many thanks so far!