After a long hiatus, I finally got back in the darkroom last night. In my previous darkroom experience in college, we had a print processor. Feed the print in one end, and a developed dried print comes out of the other. Now, at home, I've never tray developed before. The first 2 prints I developed were perfect. I slid the exposed paper in, agitated, and after probably 20 or less seconds, the print began to appear. As I got into my printing session, it took longer for the print to appear. Finally, it just stopped showing up until I increased my exposure time from about 5 seconds to 25 seconds. I'm using Ilford Multigrade Developer, and some somewhat old Ilford MG IV RC Pearl paper. Its been sealed in the plastic and box under normal indoor conditions. Enlarger is a Beseler 23C XL with a variable contrast head. I was using the VC filter set to Ilford and a grade 2. Any advice? I'm thinking the most likely thing that went wrong is the developer got colder through my session. The first test print I did was more than dark enough at a 2-5 second exposure. 2 hours later, I had to bump it up to 25 seconds to even get an image to appear at all. Its fairly cold here, and I'm pringing upstairs, which we keep cooler than the rest of the house since we dont go up there regularly. The only other thing that could have happened is me changing the apeture. I intended to start with an f8, but I was focusing and positioning everything fully open. I very well could have printed the first few fully open, the stopped down to f8 later on thinking thats what I had been doing the whole time.