Negative problem (No that's not a good thing)

I have a question about the attached negative. What happened?

I have been shooting HP4 developed in MPK for over two years, The other negatives processed in this batch were fine. (Tray process at 70 for 10 minutes) Both negatives from this holder resulted in this over exposure. What I don’t understand is why borders are also over exposed. The lens seems to be operating normally.

Any ideas? How do I prevent it from happening again?

Thanks

Since the other negatives developed in this batch came out fine, my first response would be light leaks. However, it is not likely that type of pattern would form from light leaks in the holder. Perhaps the film was briefly exposed to light in the box, or during loading into the holder.

The negatives in the photos appear to be over developed at the edges.This could be caused by developer surges during agitation. What size developer tray are you using? Are you agitating both vertically and horizontally?

A slightly larger developer tray, and using Gordon Hutchings recommended agitation pattern for PMK, will probably solve the problem.

I use 8X10 trays with a 30-second shuffle and a 90 degree rotation. I tend to be sloppy in my methods. I will watch my agitation..

I was worried about light leaks in the holder but the overall pattern confused me. My dark room is dark except for the dials on the Gray Lab timers. Would that fogged HP4?

The film is stored in a refrigerator until it is loaded into the holders. Some time it may be 3 to 4 weeks before the film is shot and processed.

This is the second time I have had this result.

Thanks for leads,

Bill,
This looks like someone opened a box of film by accident with some ambient light on and the white cardboard insert was over the top of this particular sheet and it fogged the outside edges. Could this be possible? I am not familiar with this type of sheet film, but have seen this kind of pattern when someone opened an unexposed box of film and the film was not in its foil pack.

The negative on the left was fogged before or after it was put in the holder. The other one (that shows an image) is under exposed. I can tell because I can compare the low zones to the clear film base. I cannot tell anything about the highlight density (ie development) from that scan without some reference density. But it certainly looks printable.

I have pre teen grand kids that play in my study. They are curious. Or it have been me....

Hopefully that is the only holder loaded with fogged film. I have one more holder from that pack.

Thanks for the feed back.