My first film processing disaster occurred last evening. The negative was very thin -- almost clear at first glance. Some frames are featureless or blank. This was a roll of fresh Ilford Pan F that I shot in my Yashica T5 (same as the T4 Super) between April and July of this year. I developed in Perceptol 1+1 at 68F for 15 minutes, with ten seconds of agitation (inversion) every minute. I used 300ml working solution in my two-reel Paterson tank. The top reel was left empty. Then stop (1 min.), fix (5 min.), rinse, and Photoflo -- the usual routine. The exposed leader of the film developed black, as I would expect. It's the darkest part of the whole strip. The factory edge markings, however, are very faint, which I found odd. This was my first experience with Perceptol. I mixed the stock solution over the weekend and "proofed" it with a 2-inch-square piece of litho film I exposed in my Holga. I developed that by inspection in 60ml of 1+1 for 3 minutes, and the frame came out very contrasty as I would expect. So I think the developer is okay. That leaves the camera. I shot in a variety of conditions, but mostly in daylight and indoors with flash. The roll I shot previously in that camera (in March) was Superia 1600, which came out fine. If the camera couldn't read the DX for some reason (and I inspected that -- the contacts were clean), it would default to 100. But I'm seeing more than one stop underexposure. An interesting optical phenomenon: If I hold the film strip at an angle to the light, I can easily see positive images. And, very strangely, some of the frames reveal a lot of detail, everywhere in the frame, when viewed like this. But I think it's illusory. I'll scan the film this evening, but I don't have high expectations. Very disappointing, as I had shots from my boys' graduation party and other commencement activities. Not that I put all my eggs in this one basket, but still... Any ideas what could have gone wrong?