What's Causing This Line At Top And Bottom?

[railhead]

In the picture below, you'll notice a horizontal band all along the top, and one along the

bottom. My first thought was that these are the "track marks" from the reel or something.

What are your thoughts?

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<img src="http://img58.imageshack.us/img58/6657/083fi.jpg">

[frank.schifano]

What kind of camera and developing tank are you using? From the looks of it, this is a 6x6 cm 120 camera that moves the film along the horizontal axis. Judging by the softness and vignetting in the corners, I'm gonna go a little further and guess that the camera is a Holga, that you are using a plastic tank, and agitating with the twirling stick. If I'm correct, these marks are most likely due to insufficient agitation. I've gotten similar marks with 120 film in these tanks, but not with 35mm film. For the most part, I've switched over to using stainless steel tanks and inversion agitation for these films and that has corrected the problem. However, you can do this successfully in a plastic tank. All you need do is agitate more vigorously, especially at the beginning of the development cycle. Agitate continuously for the first 30 seconds, then follow with 5 seconds of agitation each 30 seconds for the remainder of the development cycle. Each agitation cycle should consist of at least 5 complete back and forth motions in 5 seconds. That should eliminate the problem.

[railhead]

Yes, it's a Holga 120. I'm using a JOBO tank, plastic everything, with inversion agitation. I

agitate the first 45 seconds, then 10 seconds every minute after.

 

However, it sounds like you recommend doing a full end-over-end every second whereas I've

been doing that in 2 seconds.

 

The gist, though, is that the lines are probably the portions of the film that are against the

reel, though?

[frank.schifano]

Well yes, the lines at the top and bottom could be and most likely are from contact with the reel. More vigorous agitation might help that. But it also looks to me, and I could just be seeing things, as if there are some very faint lines running through the center of the frame as well. That's what led me to speculate that you were using a twirling stick for agitation.

[pete_andrews10]

Looks like inadequate agitation to me, too. Inversion agitation once a minute is generally not enough, and don't overfill the tank either.

 

Inversion agitation works by letting air bubble through the solution in the tank, and if you overfill, there's not enough air space for this to happen. I would also argue with Frank that his quick inversions probably won't give sufficient time for the air to percolate to the other end of the tank. My method is to invert, wait a couple of seconds until I can feel or hear that the bubbles have run their course, and then revert the tank. I do this this twice every minute, and not necessarily bang on the 30 second intervals.

 

I've been using the above method of agitation for, ooh, thirty years now, and in that time I can honestly say I've never had streaks, streamers or standing marks on a single film.

[frank.schifano]

Pete:

 

Sure you need a bit of headspace in the tank for inversion agitation to work properly. Doing 5 inversions in 5 seconds seems to work ok for me. Obviously, your technique is working for you and maybe I've been over doing it for all these years; but there's been no harm in it either. I don't get surge marks or any other sort of uneven development artifacts using that method and the type of tank doesn't matter. I've been doing it, like you, for a lot of years in any kind of tank that supports inversion agitation.

 

My initial, and incorrect, assumption was that Maury used a twirling stick to agitate the contents of his tank. Unless I'm especially agressive about agitating 120 film with a twirling stick, I will get uneven development aritfacts similar to, and often more severe than the example he posted.

 

Interestingly, I never get these marks with 35mm film in plastic tanks using twist agitation. The tanks hold 2 reels of 35mm film, use approximately 600 ml of solution, and leave little to no head space when used to capacity. The same sort of agitation that would normally leave artifacts on 120 film results in perfectly developed negatives with 35mm film. So 120 film always gets inversion agitation and 35mm film usually gets to play Chubby Checker. Like the saying goes, "If it ain't broke, don't fix it."

[sprouty]

For those of you doing inversion agitation: I tried something the other day that surprised me, I flipped the tank over (a Patterson 2-reel type)and waited roughly 3 seconds for the fluid settle at the top of the tank. Then I flipped it back over and quickly pulled the cover off the top of the tank and timed how long it took for it to completely drain back - approximately 4-5 seconds. Which means when I was doing inversions the way I was instructed, 3 inversions in 15 seconds once a minute, that some of the fluid didn't have time to drain back down to cover the spools.

 

That, coupled with me watching how hard it was to free air-bubbles by rapping the tank (I dropped a reel into a clear beaker and tapped and banged away) has converted me to a twist agitation process.