Last year, the film community unfortunately lost one of its manufacturers - a critical fault in machinery that could not be repaired (or so I have heard) caused Efke to shut down its film manufacturing plant. I had never used Efke products, but a good friend swore by their slow film for landscapes, and I had seen many excellent photos using their IR-sensitized film. So I decided to buy one box to try before it was gone forever.
The AURA film is special in that it has no anti-halation layer, making halos from light reflecting back from the rear of the film - an interesting effect. It was also a lot more expensive unfortunately! In hindsight, I hardly see any of this effect so I probably should've saved my money.
Anyway - I have been trying to get a good shot from this film since I purchased it with no luck. I discovered the issue finally - I was using the incorrect filter. My stupid mistake - I had assumed the "820" in the name indicated the correct filter to use. Rather, it seems that it meant how the film was sensitized - up to 820nm. So using an 820nm filter cut out everything, so my film was grossly underexposed every time.
Finally I bought a new filter - a Marumi 700nm filter, which works great! Here are two shots from my experiments that turned out well. I will have to try to find suitable shots for this special film - since I only have about 30 sheets left! Both taken with a Nikkor 120mm f/8:
Oh - I developed these in Rodinal diluted 1:100, semi-stand for one hour. Interestingly, while I carefully metered (for ISO 1!), it seems this film and development combo simply can't be overexposed. I accidentally screwed up a sheet and instead of exposing for 8 seconds, it was more like 30 seconds. Both that sheet and my "correct" sheet had pretty much identical density and range. So I probably will not even bother metering anymore - I'll just give it 10 seconds or so in open sunlight.