Dense edges of black and white film.

I just got back into shooting and processing black and white film after a many year (20) hiatus. I processed a roll of Tri-X film the other day and when I did a contact sheet I noticed that the edges of the film, the sprocket hole side, were about a stop denser than the center of the film. The contact print showed them to be about 1 stop lighter than the center of the frame. I was using freshly made up chemistry and the same procedures I used for many, many years. I am wondering, am I over-agitating the tank? I always agitate for 5 seconds every 30 seconds (3 tank inversions) with D-76 and 5 seconds every minute with fixer.

Any help here would be most appreciated!

Steve

It almost sounds like the edges got exposed at some point. Did you use a single roll or did you roll your own?

No, this was commercially packaged film and my ad hoc darkroom does not have any light leaks. It does not look like fogging or anything like that, the edges are just of a higher density. It is not pronounced enough to notice with your bare eyes, but it does show up noticeably on on the proof sheet when you inspect it with a 10x loupe. I have yet to do any actual printing yet though though if it shows up on the proofs, it should show up in the prings and then I will have to edge-dodge to even out the exposures.

Could your camera back be leaking a tiny bit? I don't see how agitation alone could affect just the area close to the sprockets... Are both sides of the film equally unevenly exposed?

This sounds to me like a case of under-agitation to me. When you agitate the film too little, or not vigorously enough, the edges of film closest to the edges of the reel will see more fresh developer then the center of the film. This results in them getting more development and hence, greater density. Try agitating more vigorously and for more time (try 1.5x what you are doing now) and see if that fixes the problem. I suspect it will. Don't forget to give the film tank a rap on the table top to dislodge any bubbles!