Problem processing negs in Jobo expert drum

I have just used a Jobo expert drum to process Tri-x negs for the first time. The film is from film packs and I think the negs are slightly bigger than regular 4x5 negs. I inserted two negs into each cylinder with the 5 inch dimension going into the cylinder, and was careful to make sure each negative was sitting securely behind the retaining ridge. Despite this, when I opened the drum, I found that several of the negs had shifted on top of the othernegative in the cylinder resulting in very uneven development. What have I done wrong - has anyone else had this problem

I've done that once or twice with normal 4x5 film. I found that I could insert the film and have the film at the top of the tube feel like it was secure, but that the bottom end might be out over the separator. That's my theory anyway - hard to tell in the dark ;-)

One way to be sure is to run your fingers down the separators to be sure that the film isn't overlapping and is therefore secure. Another way I found was to (and this is hard to describe) use both hands to grap each of the exposed corners and exert some pressure to "seat" the sheet against the back of the tube. Sometimes you'll hear it snap into place.

Basically, you just have to learn the "knack" of loading these tubes in the dark, just like you have to learn the knack for loading 35mm strips onto stainless reels for tank development. When you get it right, you get the most even developement I've ever seen for your trouble :-)

Is pack film larger than standard 4x5 sheets? Never used it myself.

If not, and you're using the 3010 drum: sounds like you inserted the film incorrectly. The 5 inch side goes in parallel to the ridges so the neg fits between the two ridges in each hole. You should be able to get two negs in each hole so they don't touch and each fit snuggly between the ridges, emulsion side facing toward the center of the drum. If pack film is larger than standard you may have to use a 3006 or other drum without ridges, or try just one film per slot (but the ridges might be a problem).

If that's not the problem, let us know which drum and processor you have and what size pack film is.

When you've inserted a piece of film, grab it by the two top protuding corners and give it a little twist left and right (bu pushing down and one corner and simultaneously lifting up on the other corner) - you'll instantly know if it is correctly seated. If it is, it doesn't go anywhere; if it is not, you'll feel the bottom shifting around and you need to get it seated. I check every piece of film I load in this manner and have, to date (grasping for some lumber here), never had a problem.

I leave the last 1 inch protruding until the drum is fully loaded. Then I push `em down and twist a little to be sure they are staying between the ridges. Then I feel the ridges to be sure the film stayed in place all they way down.

Leaving a tab sticking up keeps you from loading one on top of the other.