I have been experiencing some streaking lately (the last two developing sessions) using BTZS tubes, Efke PL100 and Pyrocat HD and would like to hear what people think may be the cause of it. The streaks range from thin lines near the sides and/or a wide stripe around the middle of the film. I have experienced this in two of the last eight sheets I have developed. I certainly keep the tubes rolling in water fairly consistently and I use enough developer (I fill the tube cap to the water line, about 250 ml). In both cases the film was one of two of the same scene from the same holder (the other film being without streaks) so I do not think it is related to my taking procedures. Thanks in advance.
Firstly are the streaks running along the long or short side of the negative?
[quote="Francesco"]I have been experiencing some streaking lately (the last two developing sessions) using BTZS tubes, Efke PL100 and Pyrocat HD and would like to hear what people think may be the cause of it.
First, are the streaks on the back of the film ( side in contact with tube) or on the emulsion side? If they are on the emulsion side I have absolutely no idea what the problem is.
If, however, the streaks are on the back of the film the problem could be that these areas are not getting any exchange of the developer during development. This would be especially true down the middle of the film since this is the area that comes into tighest contact with the tube. One solution is to pre-wet the film before loading it, and another is to load the tubes normally but while there are floating in the water bath dureing the pre-soak pop the caps off the tubes and gentely pull the film about half way out of the tube and then push it back in. Repeat this two or three times and then put the caps back on an continue with development.
My understanding is the Jobo recommends loading film wet into their expert drums since this drum is really just several BTZS type tubes rolled into one.
Thanks for your replies gentlemen.
The streaks run from top to bottom (the short side oriented vertically).
I cant see any difference between seeing the steaks with the emulsion side facing me and with it turned the other way. The streaks are visible from both ends and with the same intensity.
It could be that my presoak techniques is completely wrong or for my procedures I should do it longer. I put distilled water in the caps and then I just roll the tube as I do when developing, for about 3 mins. Maybe I should continue for another 2 as I am using less water than what you have described.
I have just finished processing two negatives from the same holder - same scene. I have modified my presoak by extending it to 5 minutes with slightly more than just gentle agitation (still using the same amount of distilled water - filling the tube caps). No streaks!