Can anyone take a stab at this?

[jmal]

I have a fairly new to me TLR and it seems to have something odd going on with the lens. On the sides of the negs, there seems to be more light than in the center. Imagine an hourglass shape in which the hour glass is darker than the surrounding areas. This is a slight exaggeration, but you get the point. At first I thought it was light falloff on my enlarger, so I scanned the negs and have the same problem. Thus, it seems to be in camera. In the attached photo, I used a lens hood and was not pointing at any direct light sources, so I think we can rule out flare (and it doesn't look like flare to me anyway). Also, never mind the photo. It does nothing for me either. It was just a test. My only thoughts at this point are that the back has a light leak or I am getting some light leakage directly on the roll itself when removing it from the camera (I always store the exposed rolls in the dark of my bag). Thanks for any thoughts.
http://www.flickr.com/photos/22163194@N04/4516387652/

 

[Thomas Wilson]

It looks like a development problem. Large tanks, inverted roughly can cause over development on the edges of the rolls. Try to be a little more gentle when inverting your developer tanks.

 

[2F/2F]

Looks like a classic case of overdevelopment on the edges with 120/220 film. It is a very common occurrence. (IME, anyhow. I work with photo students twice a week and see it often.) Are you filling your tank all the way, or is there some air sloshing around when you agitate? How many rolls are you doing at once, and how long is your development time? Are you using plastic or stainless reels?

FWIW, I notice the problem much more with plastic reels and hand inversion (as opposed to rotary agitation), though I have got it myself one time, and it was with a stainless reel and a 50% pull development.

 

[jmal]

The tank is full, but it's one of those tanks that holds two 135 reels or one 120 reel with some extra space. Development is 6 minutes for PX. Stainless reels.

 

[papagene]

Are you washing your reels with soap after your photo-flo rinse? For a while I was lazy and had this on a few rolls. Now I always wash the reels with soap and an old toothbrush right after the photo-flo rinse and haven't had the problem since.

 

[2F/2F]

The tank is full, but it's one of those tanks that holds two 135 reels or one 120 reel with some extra space. Development is 6 minutes for PX. Stainless reels.

That sounds like the culprit! Your reels should not slide up and down.

I have one of these tanks. It is all that I use for two rolls 135 or 1 roll of medium format. What I do is to throw an empty 120 or 220 spool horizontally across the top of the reel to take up the space, and then close the lid. You have to break off part of the end caps of the spool to get it to fit. The tank should always be full, even if it means using too much chemistry for the amount of film you have. A big air space at the top causes sloshing, which can cause uneven development.

 

[craigclu]

When I quit swirling and only did very, very gentle inversions, I solved this for good. I general, over time I've settled into a routine of fewer and gentler agitations. This has helped control blown highlights with most developer/film combos, too.

 

[jmal]

papagene: I don't use photo-flo, so that's not the issue. I think he others have probably nailed it. I'll try to find another 120 tank that does not have the extra space. For the record, I do fill the tank entirely, so there is no air space at the top. I never have thought of myself as a heavy agitator, but I'll make a conscious effort to be gentler. Thanks for the help. If this works as I think it will, it's a very easy fix.

 

[fschifano]

2F/2F is right about not allowing the reels to slide around in the tank, but you don't need to cannibalize a reel to take up the extra space. All you need is a tightly wrapped rubber band around the center core above to reel to keep it from moving. Using one is standard practice for me now. Works great, costs next to nothing to implement.

On agitation, you need to be more careful with medium format film. From my own experience, the problem is more often caused by not enough agitation rather than too much. It's not so much that the edges are over developed. It's more like the center is under developed. Fluid exchange nearer the edges of the film is more efficient than it is towards the center of the film, so being a little more aggressive will make sure it all gets moving.