Uneven edges on 120 negatives

[Saha]

I am getting uneven edges (negative boundaries) when I develop 120 6X6 film. What could be the reason? My 35mm negatives give perfect straight line edges. I use a Seagull 405A for 120 mm.

[blurblock]

expired film?

[Saha]

Hi Ektar,

Yes, perhaps a better way to describe it is that the image is straying into the margin area. This is happening for rolls that I develop myself, as well as for rolls that I got developed at Ruby. It is happening consistently.

[Tetrode]

Originally Posted by Saha Hi Ektar, Yes, perhaps a better way to describe it is that the image is straying into the margin area. This is happening for rolls that I develop myself, as well as for rolls that I got developed at Ruby. It is happening consistently.

Is this problem prevalent over every frame?

If yes, then I would agree with Ektar on reason #2. Check the pressure plate to see if it is seated properly and is applying pressure evenly across the film plane.

Another possible culprit could also be imperfect edges of the film chamber frame. Open up your camera's back and check the edges on the film chamber.

Seagulls are notorious for their less than sterling fit and finish.

[Saha]

thanks...but what is a pressure plate?

Originally Posted by Tetrode Is this problem prevalent over every frame? If yes, then I would agree with Ektar on reason #2. Check the pressure plate to see if it is seated properly and is applying pressure evenly across the film plane. Another possible culprit could also be imperfect edges of the film chamber frame. Open up your camera's back and check the edges on the film chamber. Seagulls are notorious for their less than sterling fit and finish.

[Tetrode]

Originally Posted by Saha thanks...but what is a pressure plate?

The 2 1/4" sq sized plate with springs holding it to the camera back. Check the links to the online manuals to find out. Unless yours is missing one, it then would explain your problems.

[Saha]

I'll try and attach a pic of the camera back tomorrow. I do not see anythign 2 1/4 "square with springs - there is a plate about 3" square attached to the camera back with screws / studs.

Originally Posted by Tetrode The 2 1/4" sq sized plate with springs holding it to the camera back. Check the links to the online manuals to find out. Unless yours is missing one, it then would explain your problems.

[Saha]

Mysteriously, my 4th roll came out perfect - edges straighter than straight lines...part of the great Seagull mystery I guess!

Originally Posted by Saha I am getting uneven edges (negative boundaries) when I develop 120 6X6 film. What could be the reason? My 35mm negatives give perfect straight line edges. I use a Seagull 405A for 120 mm.

[Tetrode]

Originally Posted by Saha Mysteriously, my 4th roll came out perfect - edges straighter than straight lines...part of the great Seagull mystery I guess!

It's no mystery to me.