C41 purple streak problem

[Rollei fan]

I have a recurrent problem with streaks when developing C41 in my Jobo CPE2 with 2521 drum. The streaks run vertically (= in the direction of the axis of rotation) and are purple on the scanned picture. I do a presoak for 3-5 minutes before developer. The rotation speed is max (2). The amount of liquids has been 270ml or sometimes more, and they have been quite fresh. Last time I loaded the 2509N reel with 6 4x5 sheets - 2 had streaks, 4 did not.

I have googled this and found several answers, but the only answer that might apply in my case is that the drum either is not perfectly horizontal or the magnet (which the drum is coupled to - I don't have a lift) is not perfectly aligned.

Is a poor horizontal alignment and uneven rotational movement (slight wobbling around the axis of rotation) the problem here? Any help is appreciated.

 

[vedmak]

can you put out a scan of the neg?

 

[Photo Engineer]

There are a lot of possible answers to this one such as red safelight fog, non-level processor, insufficient agitation, and improper bleach.

I think that this will probably be solved by the use of a 1 - 2% stop bath after the development.

PE

 

[timparkin]

I have a recurrent problem with streaks when developing C41 in my Jobo CPE2 with 2521 drum. The streaks run vertically (= in the direction of the axis of rotation) and are purple on the scanned picture. I do a presoak for 3-5 minutes before developer. The rotation speed is max (2). The amount of liquids has been 270ml or sometimes more, and they have been quite fresh. Last time I loaded the 2509N reel with 6 4x5 sheets - 2 had streaks, 4 did not.

I have googled this and found several answers, but the only answer that might apply in my case is that the drum either is not perfectly horizontal or the magnet (which the drum is coupled to - I don't have a lift) is not perfectly aligned.

Is a poor horizontal alignment and uneven rotational movement (slight wobbling around the axis of rotation) the problem here? Any help is appreciated.

scan please!

 

[Rollei fan]

Here is the scan.
And PE: no red safelight was used, agitation was at the high rotation speed setting, and the chemicals (Digibase) were fresh. What stop bath would you recommend? I have Tetenal Indicet for BW, would that be OK?

 

[vedmak]

IMHO it is not due to mechanical problems something is up with chemistry, forgive me for a stupid question, but was the temp well controlled for pre-soaking and development steps? Also was there any physical pressure (was it bent too much) applied to the film while loading on the reel?

 

[timparkin]

Here is the scan.
And PE: no red safelight was used, agitation was at the high rotation speed setting, and the chemicals (Digibase) were fresh. What stop bath would you recommend? I have Tetenal Indicet for BW, would that be OK?

Well it looks like it could possibly be a combination of things. I know some people have had problems with having six sheets in the 2509 - it is possible to do 6 sheets obviously but I would try four sheets using the inside and the outside slots to rule out that issue.

The marks certainly look like the kind you get when you don't pre-wet and you get uneven first developer contacting dry film but with a good pre-wash, this shouldn't happen

Tim

 

[Photo Engineer]

These marks could be either insufficient removal of the dyes, or it could be due to poor wetting in the bleach step. The stop I described above, 1 - 2% Acetic Acid will correct the second problem. The removal of dyes could be slowed by hard water or poor agitation, but I have run up to 6 sheets of 4x5 film at one time with no problem. Jobo does not recommend this practice though.

PE

 

[Rudeofus]

I've never tried the Rollei chems but seem to remember that they can be used at 30°C instead of the common 38°C. Tetenal recommends this if one gets uneven results at 38°C. Whether this solves your problem or not, it might gain us some insight into the nature of this problem.

 

[Rollei fan]

These marks could be either insufficient removal of the dyes, or it could be due to poor wetting in the bleach step. The stop I described above, 1 - 2% Acetic Acid will correct the second problem. The removal of dyes could be slowed by hard water or poor agitation, but I have run up to 6 sheets of 4x5 film at one time with no problem. Jobo does not recommend this practice though.

PE

PE: "insufficient removal of dyes" and "poor wetting in the bleach step". Do you mean that these streaks might be areas where bleach hasn't worked as it should?

I have Tetenal Indicet, that is citric acid, not acetic acid. Does that matter? Tetenal recommends Indicet for their C41 kit. Should be OK with Digibase too?

 

[Photo Engineer]

Bleach, if poorly spread across the film in the initial wetting of the film with bleach, can cause streaks and blemishes. In fact, Kodak states that on their web site and explicitly says that an acetic acid stop should be used in those cases. It is virtually mandatory for color paper which can suffer from the same problem.

I seem to remember that we at EK were not in favor of Citric Acid stops for color but were neutral about it for B&W.

PE

 

[Rollei fan]

Ok. And btw, PE, you are a great resource of knowledge on this forum, thank you!

 

[Photo Engineer]

You are welcome. I'm glad to try and help. Thanks for the comment.

PE