I agree. I have experience with the Rollei Retro 400S (whatever that is) in 120. Extraordinary film. I disagree with you that it's grainy though. I find it almost grain free 6x6 and above.
I suspect it's not the same as the IR product people are talking about though, because Retro 400S is
1) definitely not a 100 EI product in my workflow (not a 400 ISO film either)
2) not super contrasty at all, but that will depend mostly on development choices of course.
Also no need to waste it using a filter with it IME. It's already a strongly red sensitive film, so it's like having an orange filter always on already.
Which reminds me I should order some more from Maco.
Much grainier compared to 80. It’s perhaps a little bit less than HP5.
It’s not microfilm contrasty. But it is more than for example SFX 200.
IMO you better leave the curve largely alone and play to the films strength.
Of course you can use it without a filter. That’s what great about it compared to regular IR film.
You are not using it to its fullest however, if you don’t at least once in a while put a filter on.
It’s
meant for filtering in its aero application.
Filtering it can also be a way for taming the dynamics or lack thereof. It’s takes out the sky glow and Rayleigh scattering.
So overall the scene is more manageable and the sky is not just white, as if often the case without heavy use of dodging.