During the second round, shooting with EFKE IR820, Ye Olde Photographer took advantage of the Bronica interchangeable backs to shoot some Rollei Infrared 400, of the same scenes. We also switched to the HC110 1+47 ("Dilution E") used with the EFKE film. YOP uses HC110 in one-shot mode, mixed directly from the syrupy concentrate, so that reduces the amount used.

With the Rollei film, YOP still feels the 720 nm filter, while providing much faster exposures, is a little less reminiscent of the Kodak IR results he saw in days of yore. And yet, an 89B filter is about 695 nm cutoff. YOP theorizes this is because the actual spectral sensitivity curve of the film is much more skewed toward the visible green and blue spectrum than the old Kodak IR, reducing the effectiveness of the lower cutoff filters. In that regard, the EFKE material appears to have the edge, although even it doesn't reach the results of the old material. Net: YOP might still lean toward the 760 nm filter in bright sunlit scenes with the Rollei film, but agrees his earlier disappointment with the 720 may have been more a matter of exposure and scene lighting.

Across the bottom two rows, a few shots are paired, Rollei Infrared 400 on top, EFKE IR820 below.