Topic: Film Developing halloween nightmare! - Follow up #2

[Nigel]

Sorry if I'm flogging this one, but it's really bugging me. I posted my film mark problem on one of the APUG forums just to see if I could get some different suggestions. One of the posters suggested it look like pressure marks on the film. Looking in the back of the Yashica Mat I saw these two 'lugs' which hold the pressure plate in position. As close as I can tell they're on exactly the same line as my mark - could that be the issue?

If so I don't really know what I could do about it as they're not adjustable. I didn't get marks on the XP2, are some films more sensitive to pressure marks than others?

What'd ya think?





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[Nigel]

Sorry wrong pic - try this one.

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[Pete_R]

I think it's very unlikely the studs are making contact with the film unless the springs behind the pressure plate are knacked and are allowing the pressure plate to fall backwards and making the studs stand proud of the plate. If the plate feels it has plenty of spring tension in it and the the studs seem firm (that is, they haven't come loose) then I don't think this is the answer.

If you want to check, you could try inking the tops of the studs with a felt tip pen (one that doesn't dry too quick) and then put a piece of paper in the film position and close the back. If the studs are touching, they'll leave a mark.

[Nigel]

Hi Peter - you're right I jumped the gun. It's the film tensioner, I put one of the negs in there and it's in exactly the right position and the spring on that thing is really quite strong.



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[Pete_R]

Ah right. So this looks like it is something to do with stressing the film after all. When I had the problem with stress lines I thought it only happened with the T grained films but maybe it happens with others as well, but not all types which is why you don't always get it.

Does it look like you could reduce the tension on the spring?

[Nigel]

That's the strange thing, the mechanism is deep inside the wall of the camera, there's no adjustment. So how come everyone doesn't have the same issue? and I didn't with XP2. Is it something about Tri-X? Sorry Peter not really expecting you to answer these questions, but it is weird.

I know Skorj has the same model, maybe he has had the same problem.

[Francois]

Actually, I would try and not fiddle with the knurled ring. It's used for the frame counter and film advance stop. Its diameter needs to be exact for it to function properly. I've tried mine with some Kodak film before and had no problems. Maybe their backing paper was thicker in the days...

[Skorj]

Hmmm... I would have thought the frame-counter drive was outside the area of exposure, but if not, then perhaps it could be the cause. Assume you are shooting 120, and not 220?

I will check mine tonight when I get home and update on suspected position of the drive...

Regardless, I have shot a variety of 120 and 220, mostly C41 stuff, and have never seen a mark on my negs. Skj.

[Pete_R]

Interesting what Skorj says about the wheel being outside the image area. Is it possible the wheel has moved up the shaft and into the image area?

Thinking about it, if you were using 220 film with no paper backing this wheel would be resting on the film and it doesn't seem right that it would do that in the image area, even if it is on the back side.

[Francois]

I just checked my Mat and the counter wheel truly is outside he frame area. The wheel seems to be press fit on the axle so I doubt it would move. Both chrome rollers need to be free spinning so it could be worth checking these out too...

[Skorj]

I just checked my Mat and the counter wheel truly is outside he frame area. The wheel seems to be press fit on the axle so I doubt it would move. Both chrome rollers need to be free spinning so it could be worth checking these out too...

That is indeed the case on my Mat too:



How much of a crop have you given us above, as the line appears to be well within the image area. As you can see from above, the frame-counter drive wheel is outside of the line of the film guides, and should not have any effect on the image area. I chewed some marks in a spare spool to check the location, and you can see again they're outside the film guides. We need to look closer! Skj.

[Nigel]

Hi Guys

I'm at a loss, there is a small amount of sideways movement on the spindle the drive wheel sits on, but maybe not enough to be the cause. When I'd originally held the negative in position I hadn't remembered that the backing paper on 120 is wider that the negative itself so the negative isn't quite where I thought it was.

I don't know I'm now at a loss! I'm at the point where I need to stick another film through it and see what happens.

my Mat:





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[Francois]

Your Mat looks just fine to me. If the chrome rollers are free spinning and in good shape, I can't see the problem coming from the camera itself...

[Skorj]

I can't see the problem coming from the camera itself...

They were going to be my next words too! Skj.

[Nigel]

Mmm.