I got interested in infrared photography in the early 1970s. But the only IR film available at the time, Kodak High Speed Infrared, was grainy and relatively low in sharpness so I was never really happy with the results. One day everything changed. Looking at Minor White’s monograph, Mirrors, Messages, Manifestations, I came across a section, Sequence 10, of infrared photos that were impressively sharp and detailed. It hadn’t occurred to me that infrared film might be available in sizes larger than 35mm. That day I ordered my first box of 4×5 infrared and continued using the product until Kodak discontinued it over 25 years later.
When everything worked, shooting large format infrared was great. But for every wonderful surprise there were an equal number of mishaps and at close to $2 a sheet there were limits to how much experimenting I could do.
Choosing a camera filter to use with black and white infrared film is pretty straightforward. There is the “standard” IR filter that passes a small amount of visible light such as the Hoya R72 (now labeled RM72), or the similar B+W 092. The other option is the darker B+W 093. I own all these filters, including Kodak’s 87C and the discontinued Hoya RM 90, and where black and white film shooting is concerned the biggest difference I’ve found is the exposure time. Not surprisingly, the 720nm filters that pass some visible light allow much shorter exposures than the 900nm types. It’s true that with a 900nm filter you will often get a somewhat darker more dramatic sky but the RM72 or 092 also perform well when it comes to dramatic skies and exposure times are significally shorter.