c41 processing marks

[AbsolutelyN]

Hi

I've been having issues with marks on c41 negatives for some time and I wondered if anyone has thoughts on the most likely cause(s).

I've developed hundreds of 5x4 sheets in my jobo cpe2 over the years but for about two years now I've had seemingly random marks or stains on the negs. When I first started developing my own negs I had no issues for at least 18 months and I cannot quite figure out what changed. It seems to affect only two to four sheets in a batch of 6 or 12. The marks usually but not always have a colour change in them.

I always presoak negs for at least 5 mins to ensure they are at the same temperature as the developer. I did not used to do this and had no issues - not doing it seems to make no difference. The issue tends to affect 5x4 sheets only - 120 and 35mm I've never noticed any issues with (that's why I tried longer presoak with the 5x4 sheets being thicker).

Things I'm thinking it could possibly be are:

Bubbles under the negs causing uneven development in the area of the bubble

Splashing as the chemicals are poured in - but to me the stain shapes and sizes dont make this seem a likely explanation.

Here is an example - the image has been darkened to emphasis the mark. Any thought appreciated as this is randomly ruining my images as I develop them.

Finally - I think these marks are actually quite subtle - scanned on a Imacon Precision II they are nowhere near as visible as when drum scanned.



Cheers
Tristan

[dave_whatever]

Are you using the black plastic paddle things on the reel or not?

[AbsolutelyN]

Hi Dave

I have two reels - one with the paddles and an older one without. I always use them on the reel that has them. Usually I use both together in a larger drum - it seems to affect film on either reel. Developed individually in a smaller tank I've not noticed any link to one specific reel. Originally I had the one without paddles and always got perfect results with it.

Thanks
Tristan

[Jonathan Perkins]

I'm not sure its splashing of the developer Tristan - I had a 120 film that after pouring in the dev I fumbled fitting the lid such that the film sat for a second or two with half in the developer. That resulted in a nice line down all the images, with one side more dense than the other. I just looked through the ones I scanned again, and I can't really see any significant colour shift like you have. Also the line has a much sharper edge (although I didn't pre-soak, so there may have been a surface tension effect that stopped it spreading?).

Does it make any difference if you have 4 or 6 sheets on a reel?

When you remove the negs after processing it may be worth noting the order in which they come off for a few times, in case you can deduce if its inner, middle or outer position?

Jonathan

[AbsolutelyN]

Thanks Jonathan, I don't think it's splashing either, bubbles are my current possible theory - I'm planning on ensuring everything is level for the next batch. I think I've also experienced what you describe but not as often as this issue. I'm pretty sure it's the outer negs mostly affected when I've noted order negs come out.

Anyone know if stabiliser can cause staining under any circumstances?

Thanks
Tristan

[Baxter]

I too initially thought it might be the paddles Tristan.

Are you putting the stabiliser in the Jobo tank? I read somewhere that this was a no-no and so I always did the stabiliser bath in a Combi-plan tank after I had removed the sheets from the reel.

Thus if it is a stabiliser driven issue, it is more likely to affect the outer sheets.

[AbsolutelyN]

Hi Baxter - that's really interesting thanks. I've not come across issues with the jobo and stabiliser before. I do put it in the jobo with just a small amount of agitation to ensure it covers the sheets evenly. I think this could be the issue, I'll dig deeper. Thanks Tristan.

[Chris Wilding]

Hi Guys

I think you might be on to something with the stabiliser, as far as I know it was not recommended to use it in the processing drum as the formaldehyde element would actually attack the plastic roughening the surface over time and would making contamination more likely, however the new stabilisers are low or no formaldehyde I believe, I would be interested to know whether formaldehyde is still an ingredient in Tetenal and Fuji? Anyway I have a separate dedicated tub for the stabiliser in case.

Hope you get to the bottom of it.

Cheers

Chris

[AbsolutelyN]

Thanks Chris. I'll be developing a batch of negs in the next few days so will try using a combi-plan tank for the stabiliser. Thinking back the point at which the issue first occurred it was when I tried a different make of chemicals from Fuji which I had always used (for hundreds of sheets with no issues). I swore never to use Tetenal chemicals again as there was staining all over the negs. I have had intermittent issues ever since. I always give my reels and tanks a good rinse but I'm wondering if I need to give them a good scrubbing or even replace them.

[gary mulder]

Try cleaning with a fizzy for dentures. That works for me on second hand jobo drums.

[AbsolutelyN]

Thanks Gary, I shall try that. Tristan

[AbsolutelyN]

Just a quick notes to say thanks for all the suggestions. I think I have this under control now - not perfect as I think there is still some contamination of the reels causing excess development at the edges of the negs but the improvement is huge. I dev'd some negs last night and they are the best batch in a long time - blank overcast skies with no sign of any marks or stains anywhere. I'm 99% sure it's the stabiliser causing the issues - it will never be going near any jobo tanks or reels ever again and negs will be dipped in a tub of it at the end.

Thanks
Tristan

[Martin Jan Köhler]

Hi Tristan,

yeah, never put the Stabilizer in the Jobo drums!

Just use for example something like a Tupperware box with a lid,
you can then also reuse the Stabilizer over two weeks or perhaps even longer ...
I keep it closed as much as possible (even after inserting the film),
so that no large amounts of dust will accumulate ...

Just be sure to write something on the box like "contains formaldehyde. not for foodstuffs!",
those boxes are simple to confuse and the Stabilizer box is not so healthy to be used for foodstuffs
(at least for me it's a problem, as my kitchen is my "darkroom" ... or is it "lightroom" with the Jobo then? )

Best regards,
Martin