Dark Bands on b/w Negative

[christian_welham]

<p>I'm fairly new to film processing (about a year into it) and have probably processed around 40-50 rolls, but came across something earlier that I've never experienced before. The film of HP5 at 400 ISO I processed has multiple dense and dark vertical bands at varying intervals throughout its length. I don't currently have access to a scanner so have posted some photos of the film, which doesn't show the bands too well so I apologise!<br>

The photos were taken on my Zenit B in Italy about a week ago. I took the film through airport security in my check in but was not allowed a hand check of my luggage. The film went through the scanner once, but I do not think the bands are due to X ray fogging as I have developed two other rolls from the trip without the same issue. As the film is mid speed I wouldn't have thought that X ray fog would give such obvious irregularities!<br>

This was the second to last roll I took however before the shutter/film advance broke and became too gritty to use. On the last roll I shot, the advance mechanism seized up and I couldn't advance the film smoothly and it became gradually worse until I couldn't move it at all, meaning I had to abandon the roll midway through. I have changed the spring in the camera now, and it runs smoothly, so I can shoot another roll tomorrow to find out whether it was a problem with the camera rather than the processing.<br>

The interesting thing is that the first 5 or 6 exposures on the roll (the deepest in the reel) came out fine and the banding starts from around exposure 10 until the end of the roll. The spacing in between the bands varies from around 2 or 3 in a single exposure to about 6 in some. There doesn't seem to be any pattern in the distribution of the bands.<br>

I developed the film for 13 minutes in fresh 1+1 ID 11 at 20 degrees, with 3 taps on the bench followed agitation every minute for 10 seconds. I have read about "bromide drag" but that seems to give more equidistant bands and the examples of it I have seen seem to be a lot more subtle in density. The rebates on the film show no signs of light leaking and appear to have been processed normally, and the vertical bands do not extend to the rebates. Could this indicate a problem with the shutter before I fixed the camera? The Zenit has a focal plane shutter with no obvious problems with sticking etc.<br>

If anyone could give me an indication to what may be the cause of these bands, I would be very appreciative! As far as I can tell the problem is either due to: X ray fogging, an issue with the shutter/advance from when the camera started to fault or bromide drag from over/under agitation, but I have no clue! Im apprehensive now to develop any other rolls from the trip incase its fault with my processing rather than the camera.</p>

<p>Photos:<br>

[glen_h]

<p>I think you need to scan them.</p>

<p>Between the lighting and the shadows, I can't see enough to tell.</p>

<p>When you say "dark" do you mean black or another color, such as brown?</p>

<p>X-rays should be less of a problem for 35mm, as the metal cartridge shell will protect it, and also the metal camera body if it is in one. But at the right angle, the beam could go in the end of the cartridge.</p>

<p>It is a scanning beam, so makes lines at funny angles across the film, as it is rolled up. They wouldn't normally be vertical, unless you were very (un)lucky. </p>

<p>Vertical bands near the beginning of the roll are usually light going through the light trap. It isn't quite as good as you wish, and direct sunlight can get in just a bit. </p>

<p>Or it could be camera light leaks.</p>

<p>US airport X-rays are supposed to be safe to ISO 800. So the signs say. But they will hand check if you ask. Since I often use Diafine, with an increased EI, I often ask for hand checking.</p>

<p>Other countries might use different systems.</p>

[thirteenthumbs]

<p>Open a new document in a text editor or new document in Photoshop with a white background and open to full screen. Hang/hold the negatives in front of the white screen then photograph them with your digital camera/cell phone.</p>

<p>From what I can see in picture 2 and 3 of your currently posted images strongly suggest the shutter is not running consistently during exposure. The camera has a horizontal travel focal plane shutter consisting of two curtains. Cocking the shutter winds both curtains onto the right roller and sets tension on the rollers. Releasing the shutter curtain 1 starts to to move onto the left roller then curtain 2 releases according to the speed selected and forms a slit that exposes the film. The curtains must run smoothly to make an even exposure. An erratically running shutter will cause segments of over exposure, shutter sticking or running slow briefly, or segments of under exposure if the curtains are running too fast.</p>

<p>What I'm seeing as bands are limited to the image frame which eliminates processing. The camera needs servicing.</p>

[christian_welham]

<p>Ive attached some better photos, hopefully they'll be a lot clearer! <br>

I personally agree that its most likely a problem I had with the camera at the time. Would issues with the film advance lead to problems with the shutter sticking etc? Now that Ive fixed the film advance with a new spring would that most likely solve the issue? I guess its speculation at the moment and theres no way of telling until I run some more film through it.<br>

[christian_welham]

<p>Could it be an issue with the fixer I was using? Ive just read that old fixer can give you bands on the negatives. Would refixing resolve this if that is the case? Or can processing issues be ruled out due to the consistent clarity in the rebates?</p>

[thirteenthumbs]

<p>I've heard of weak fixer leaving film milky and fixed unevenly but not streaks. It will not hurt anything to refix the film for an additional 10 to 15 minutes even with fresh fixer.<br>

If the images do not improve after refixing then its the camera. The shutter tensioning spring(s) are a different from the wind spring. Debris in the shutter curtain path will affect shutter operation also. With the lens off and back open lock the shutter open on B and inspect the shutter path. You might be able to see the uneven speed of the shutter curtains on B also. The curtain open/close should be a quick snap from one extreme to another.</p>

[christian_welham]

<p>after inspecting the shutter, everything seems to be working perfectly. Very stumped on this one</p>

[doug_armstrong]

<p>Christian, Charles is right. It is almost certain that it has nothing to do with the processing. The bands stop at the edge of the image; there is no hint of them in the unexposed edges of the film. The processing chemicals know nothing about where the image ends.</p>

<p>The bands are areas that received more exposure than the rest of the image. From what I can (not) see, I don't know whether the bands have been exposed for longer or whether they have received non-image light. You should be able to tell which by finding a place where one crosses adjacent very dark and very light parts of the image.</p>

<p>Now to speculate wildly. I cannot image a mechanism by which non-image light would get in to the film while it is in the film gate. Therefore, I will guess that the second focal plane curtain is "stuttering". That is, as the curtains are crossing the film gate the second curtain is periodically (we're talking milliseconds, or perhaps microseconds, here) getting stuck and then catching up to where it should be. I know absolutely nothing about the mechanical design of the mechanism which controls the curtains. That is why this is wild speculation.</p>

<p>To state the obvious: Unless you have mechanical skills that you have not hinted at, you will have to get this to a camera repair person if you want to get it fixed.</p>

 

[bethe_fisher]

<blockquote>

<p>This was the second to last roll I took however before the shutter/film advance broke and became too gritty to use. On the last roll I shot, the advance mechanism seized up and I couldn't advance the film smoothly and it became gradually worse until I couldn't move it at all, meaning I had to abandon the roll midway through. I have changed the spring in the camera now, and it runs smoothly, so I can shoot another roll tomorrow to find out whether it was a problem with the camera rather than the processing.</p>

</blockquote>

<p>If the new roll looks fine then I'd say the problem was likely with the spring that you changed. The issue looks more like a camera problem than a processing one.</p>