At one point Filmulator took in linear TIFFs, but when I made the GUI I never added that functionality back in. It would be possible to add that back.
I’m not sure what I want to do about inverting DSLR scans of film. Part of me wants to shout “You already shot film, why do you want to simulate film on it again!?” The other thing is that a lot of the look of Filmulator is really baked in and not adjustable, and I’m not sure how well it will work on something very different from the extreme linear response of a camera sensor.
Personally for now I think I’ll leave inversion out, and add linear TIFF importing back in. Shouldn’t be too hard, plus it would let you import panoramas and such, though it’s cumbersome to work with linear files.
Could you upload some samples of your inverted negative TIFFs for me to try out? Ideally, exported with linear gamma in 16-bit integer.