I have recently had problems with a streak, or rather a transparent, diffuse thin line (not a scratch) that runs along the length of my Tri-X 400 120 negatives. It is clearly visible against evenly exposed areas of the film (e.g. the sky) and has been present on four out of the last five rolls I shoot (all probably from the same film pack).

Strangely enough the line is always in the same place (exactly) on the film, slightly off the center of the exposed 2 1/2 x 2 1/2 inch negative and only shows up on exposures 1-6 (12 exposures/film). The effect has been more prounouced on two of the films. It's hardly a drying mark (I use photo flo) and since the line is always in the same place I find it difficult to believe that it is due to uneven development or incorrect agitation, but I am not certain about this (I have read the earlier postings on film streaks). I pre-wet the films and develop in D-76 1+1 for 10.5 min at 20 degrees Celcius and use 500-600 ml developer/film (Paterson super system 4 tanks). Continous agitation (inversion of the tank) first 30-40 s, and for 5 s every half minute for the rest of the time. I have not had any problems with this earlier, but I am relatively new to 120 film. At the moment I suspect the fault is in the manufacture of the film (I have not yet developed film from a different pack). The film expires november 99 (lot nr 840173). Has anyone had a similar problem?

Per Askerlund

-- Per Askerlund (per.askerlund@plantbio.lu.se), February 04, 1999

Answers

If this is a clear line on the neg, be sure to check for a hair, spiderweb or something in the camera film gate or magazine.

-- John Hicks / John's Camera Shop (jbh@magicnet.net), February 05, 1999.

Two years have passed since I wrote the original posting. I still suspect the fault was in the film, since it did not show up on film from other packages. Last week, however, I noticed the same mysterious streaks (weaker this time, but on exactly the same place) on a newly developed Tri-X film.

-- Per Askerlund (per.askerlund@telia.com), February 13, 2001.

Is the line _density_ if not a scratch? Or iow, is it a darker line in the film that prints light or white and runs lengthwise?

If so, there's something the film is running across, front side or back side, that's making a pressure mark but isn't under enough pressure to actually scratch the emulsion (front side). Some films are more susceptible to such damage than others

-- John Hicks (jbh@magicnet.net), February 13, 2001.