Mysterious vertical lines departing from the highlights

[Charles-Olivier]

Hello friends,

I have been processing a bunch of long exposures recently and I keep encountering these vertical lines departing from the highlights. They only happen during long exposures done on my Bronica SQ-AM. I have already established that the lens was clean and that it wasn't bromide drag. Could anyone help me figure out this mystery?

Thanks in advance!

 

[Nicholas Lindan]

My understanding of the SQ-AM is that the film advances in the downward direction with the top of the picture being the direction of advance. The camera has a leaf shutter and film advance and shutter operation are all electrical/electronic.

If this is so, my guess is that the camera advanced the film before the shutter had completely closed. Do the streaks continue into the next frame or into the space between the frames?

 

[voceumana]

I think it might be some flare reflections. If you look at the highlights on the column to the right there's obviously some light source(s) providing the highlight and it could be reflecting off some of the glass in the windows, and then within the lens.

 

[cramej]

That looks very much like the shutter is not closing when the film is advanced. You can see streaks from every light source in the photo.