Grain35 v2.0 is real film grain, scanned by using a special Arri scanner. The people at Crumplepop took it upon them to scan 16mm and 35mm films and wrapping them in a Final Cut Pro X plug-in.
Grain35 v2.0 is an upgrade from Grain35. Grain35 v2.0 is a great plug-in. All grain assets are now in Rec. 709 colour space. The saturation slider introduces a colour cast, which is the natural colour of the grain emulsion. For example, Fuji stocks are slightly more blue than Kodak stocks. The saturation slider lets you control how much of the natural grain colour you wish to apply.
CrumplePop Grain35 v2.0 was created using 4K Arrilaser DPX scans of six different 35mm and five different 16mm film stocks. This enables you to use the 1920×1080 version of Grain35 v2.0 with your DSLR footage, and the 4K version with Red Scarlet/Epic footage.
You should select the grain closest to your white balance. For example, if you shot in shadowy areas with bright sunlight in the background, chances are your white balance will have been close to D65. In that case, choose a grain that has been scanned with daylight conditions in mind (a “D” is added to the name). When shooting under tungsten light, the “T” is what you’re looking for in the effect name.
When you select a 35mm grain, the effect is subtle. A 16mm grain is much more robust in its look and feel, but which of the two you choose depends on the subject of your movie, of course.