Partially underexposed, on some frames?

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Morca007

Matt
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I have been having sporadic problems with:
-Sprocket holes leaking light onto frames
-A third of the frame, clearly delineated by a line, underexposing by a stop

Now, this only seems to manifest itself on film out of my Bessa R.
Stephen suggested that I try shooting some color film in it to check if it was a shutter problem. Now, I have thus far not replicated it with C-41 dropped off at a 30 minute photo.
So then it should be a developing problem, yes?

But then why does the problem not manifest when I shoot with either of my SLRs? The developing process has not changed.

I am currently using an Adorama plastic dev tank, plastic reels (space for two 35mm, or one 120mm), doing one roll at a time.
Mixing 300ml of chemicals, doing the 10 seconds of agitation recommended every minute.
I am fixing properly and drying right.

What is going on? :bang:
Any ideas?

Example attatched exemplifies the two problems, though they are not always together. Blank wall, 1/60 at 2.0.
 

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Could this be related to the level of developer in the tank? Are you certain you have enough developer to cover the film with plenty to spare? Is the effect the same along the whole length of the film? Does it show like this through the blank space between frames?
 
That is a weird thing, let's try some troubleshooting...

It seems to be a camera related problem, since you said that your SLR-exposed films comes out fine.
To rule out camera problems let's think of where in the camera this could be originating and my thought goes to the film window in the back... Try covering the film-window with some tape to see if that helps.

Have you tried shooting 1/2 roll in the Bessa and 1/2 in the SLR to see what happens? If the problem reproduces in the bessa half then you can be sure it is a acamera problem
Or just shoot only 20 exposures and develop to see if the blank frames have problems.
Since the camera is new I can't see any other place to have problems.

How do these sprocket strips look like in the negative?
Are they milky or are they solid black?
The 1/3 underexposure bugs me so I do not know what else to say.

Have you checked your C41 negatives with a loupe?
 
Classic uneven developing marks. It could be you have too much chemistry and as you invert the tank, the movement of the reels increases development at the sprocket holes. With proper agitation and chemical movement, you should not get these
 
ChrisN- The effect is the same, but it only shows up on certain frames.

titrisol- I use a half-case, so the window is covered.
The spaces between frames are completely clear.
Sprockets do look somewhat "murky" in some places.
I do not have a loupe, but I assume I would see the effects if they manifested on the C-41 frames.
 
The sprocket hole streaks look like "bromide drag"--a problem of insufficient agitation, sometimes associated with the design of the reels. Try agitating 5 sec. every 30 sec. of development time instead of 10 sec. every minute.

I'm not sure what kind of shutter the Bessa has, but were you using flash? If you have a vertical-travel focal plane shutter and are using flash set at the wrong speed for flash sync, you'll get bands of unexposed area in the frame.
 
It is a vertical travel, but no flash was used.

The next roll I develop, I will try the every-30-second agitation. Should I curtail dev time a bit to compensate?
 
Open the back of the camera and shoot against a bright background at different speeds, and see how the shutter behaves. Its easy to see of the curtains dont open properly. Try every speed several times. I have a similar problem with my Pentax ME Super, but only on 1/2000th.
 
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