I typically use Ilford SFX-200 as my IR-Sensitive film.  When I started, I used it with my darkest red filter:

But now I use my IR-695 filter:

Recently I’ve had two IR-sensitive film come my way: Rollei Retro 80S and Washi-Z.  Let’s start with the Rollei film. Because of my positive experience using the 695 filter, I tried this with the Retro 80S.  It resulted in interesting but very high contrast images:

Compare this to T-MAX 400 with a Dark Red filter (sorry that’s the film I had in the other Mamiya-7 at the time):

Here a direct comparison of the same scene, SFX-200 and Retro 80S, both with the IR-695 filter:

Can you tell which is which? The Retro 80S is the upper image, the SFX-200 is the lower image.  The SFX image preserves the fine high altitude clouds better…..

I have recently read an article on the Retro 80S, where the author only used the dark red filter.    @EMULSIVEfilm also has another recent article comparing Retro 80S and Retro 400S, again both using the dark red filter.  So now I’m going to embark on a set of side by side Retro and SFX images making, using only the dark red filter.  Can’t wait to see what happens……

Washi-Z discussion coming in Part II.