Film Problems and their causes

Barney

Barney

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Wayne
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Just done the light seals on Mamiya,

first roll fine, second roll first four shots fine then 5 shots with this stripe then last shot fine.

the light stripe on the photo is of course dark on the negative and extends beyond the frame of the photo right into the actual film edge.

any suggestions?

annoying.jpg
 
VirtualAdept said:
straight edge like that suggests a light leak of one of your new seals I think.

This is the leak I got using one of those plastic DIY TLR's

DIYTLR-kentmere400-510pyro_ 3 by Madison S, on Flickr
Click to expand...

Would that not be within the frame through? This is top to bottom of the roll (120) as though it has happened after the shot, my preliminary thought were the darkslide as its such a crisp edge. I had put another flipping roll in as well before developing this so ...... cant check the back really.
 
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Barney said:
Would that not be within the frame through? This is top to bottom of the roll (120) as though it has happened after the shot, my preliminary thought were the darkslide as its such a crisp edge. I had put another flipping roll in as well before developing this so ...... cant check the back really.
Click to expand...

I'm not really sure I understand. The light would reach from one edge of the film to the other, so outside of the frame itself.
While you could be right about the darkslide, it'd still mean there's a leak as its supposed to still be light tight when the darkslide is removed
 
VirtualAdept said:
I'm not really sure I understand. The light would reach from one edge of the film to the other, so outside of the frame itself.
While you could be right about the darkslide, it'd still mean there's a leak as its supposed to still be light tight when the darkslide is removed
Click to expand...
darkslide is the only seal I did not change, perhaps when inserting darkslide it is some how opening a seal. I need to recheck everything I think.
 
As I said there is already a roll in before I developed the other one and noticed the fault,

I used other cameras since as I did not want to waste a full roll of colour film,

I have effected this temporary repair until the roll is used so I can dismantle and see whats going on, will it be effective at stopping the light getting in do you think?

taped up.jpg
 
Not as effective as a double layer of decent black insulating tape.
 
Nod said:
Not as effective as a double layer of decent black insulating tape.
Click to expand...
I didn't have any black and I was about to go shop and get some when I found the red
 
Since I can read text through it, I guess it's not light-tight...
 
I will get some more tape.
 
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I think I have figured this out, I hope so.

The most recent roll has One affected image so the light is not getting in through the back.

I have a feeling that after the light seal replacement a spec of old foam seal has become trapped at some juncture of the baffle causing it to not seal correctly and let in some light.

I have just given it 20-30 actuation's with a good blow out between each one and although not a great deal of old foam has come out there was just enough, and one or two of the right size, to enable me too hope that this was the cause.
 
Finally got to the bottom of this I will report it for future reference of any one in a similar situation with the sharp well defined line.

It is the rotating back light seal, two strips top and bottom 7mm x 95mm.

I noticed a small amount of movement in the back where it connects to the rotating back, I suspect that over time the rotating back seal has worn and is allowing an ever so slight amount of movement when the dark slide from the back is inserted, particularly if not lined up 100%. That is probably why its intermittent, sometimes you drop lucky with the darkslide insertion.

After I noticed the slight "play" I checked the spec and it was for 1.5mm foam so I used 2mm to provide a more effective seal and more resistance to the torque when inserting the darkslide. The flipping fasteners under the foam seal don't help, they stand ever so slightly proud thus the foam in that area gets worn faster.

Just developed a roll and checks out ok. Yaaaaaay !
 
FFS, I could curl up a corner and cry, full ten frames ok the other night, now half the roll is shot.

There is only the darkslide holder Velvet left and its had the full hit
 
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