I have been playing with PMK for a month or so. The first few rolls were HP5+ , 35mm that had been in the fridge for awhile and out of date. The rebate stained as well as the exposued sections. I wasn't aware that that would happen and when checking around was told that it was due to the out of date film. No problem, negatives printed fine. Another up todate roll developed without staining the rebate. Tonight I developed several rolls of Hp5+ , 120 with out of date of 2005. Rebate staining again. The negatives appear fine and will probably print fine. Just wondering about the rebate stain. Is this a normal condition.? i am not going to lose any sleep over this, just wondering what is going on.