>>3403363T-Max 100, real world is about 100 lp/mm with a sharp lens when used well - and that requires excellent scanner or enlarging lens.
So around 30-35mp for 35mm for T-Max 100.
HOWEVER.
It is particularly rough and very low contrast at that range, and becomes barely visible.
Digital remains smooth, clean, and high contrast all the way through (only lens dependent).
To get back to a reasonable contrast, its around 12mp-15mp. But still 12mp digital sensors produce better IQ (apart from not having the higher frequencies).
Even for T-Max 100 I would shoot medium format. Rollei Retro 80s has similar real resolving power to T-Max 100, but much finer grain, can be used well at 50. So its a possible choice for 35mm.
Hence why we go to 6x7 etc, especially if we want to use Tri-X or any other film other than T-Max 100, Delta 100 etc, or even colour (Ektar is quite smooth, but is soft/lacking resolution, Fuji C200 destroys it in sharpness, but is very grainy and only available in 35mm).
On colour in 6x7 while it can actually resolve higher, its better to consider it below 20mp, as higher the image will be rough, in some cases quite patchy in the shadows with grain (that can look hot noise in some cases) - can be worth exposing a bit higher and bringing it down in those cases. Ektar might be a bit better in this case, even though its the lowest resolving in the main colour films, its much smoother.
