Film Grain in Capture One 8 is a simple affair. It’s not comparable to the film grain you can have with DxO FilmPack or Alien Skin Exposure. Far from it. But Phase One has a straightforward explanation on this issue. I asked other film grain developers about their practices and the results you can get and this is what they have to say.
Phase One does not try to emulate a specific film (e.g. Kodak TriX 400), but only draws inspiration from them. They say there are simply too many variables. Most film grain features base the grain on scanned film stock, usually a small tile and sometimes huge scans. Phase One believes the scanning method is flawed as a scan cannot simulate all situations of an organic film which behaves in an infinite number of ways, depending on image content, exposure and other factors. By using mathematical modelling they claim not to be limited by a few scans of film stock but able to more accurately simulate how the film grain should look based on multiple factors.
At DxO Labs, the developers of DxO Filmpack, they do scan high res samples of the grain to get precise results, but the technical chap I got the answers from didn’t have the tile size they use at hand. At DxO Labs, they are not aware of any limitations their practice could impose on the user. However, one of their users reported once that the repeating pattern of the grain was visible on his photos. The photo itself had a very large size print (gallery size), while the user had applied a very small size of the grain. The photos had a lot of uniform areas. DxO Labs says it will improve on that eventually, but they have not done so yet.
DxO Labs scans the grain pattern for several levels of grey, and the company applies it on the image taking into account how the light level affects the grain. The size of film (and consequently grain size) can be customised when applying the grain, but by default they apply it as if the output is a 24×36 photo. As for other parameters (sensitivity, development parameters), they only shoot films with their advertised sensitivity, and process them with a standard process. That also applies to other film parameters (contrast, colours).
As for best matching results, their presets deliver film rendering as measured in their lab — which means that a user who is interested in fidelity can use them as is. Others can tune endlessly: grain intensity, size, mixing grain type with the rendering of another film, etc.
I also asked Grubba Software, but they haven’t replied. Grubba Software scans film with a very large tile size.