Try PMK or Pyrocat-HD, both at 12.5 minutes, 70 deg. F., EI 100. I have a pinhole camera in 6x9 format and did some calculating--there is a full stop difference in the exposure at the center and the exposure at the far edge, so I've gotten in the habit of overexposing by a stop, but that shouldn't be necessary for smaller formats.(posted 8227 days ago)