Film grain versus digital noise…


Without drilling down into the technical differences, let's just say there are differences and leave it at that.  There are digital techniques available to duplicate the film grain effect, but here is a very simple technique that actually uses the grain itself.

Film grain has a subtlety that is difficult to quantify and different films have different aesthetics.  High speed films (greater than ASA 800) have a gritty granularity that was both random and continuous.  This was a popular film speed for mid-20th century photojournalists that allowed them to shoot quickly without an outside light source.  Because it was so common, it became familiar.

Two popular Kodak films were Tri-X 1600 and T-Max 3200.  These were very high speed black and white films with relatively large film grains.  Here is an easy cheat to re-create that film grain effect on a digital image.

Open either of these two links and download to your desktop (tri-x_1600.jpg and t-max_3200.jpg).  These are actual scans of an 18% gray reference card shot with these films.

To duplicate the film grain effect, open your image of choice (and it should be an image that would be appropriate for a grainy image) and convert to a gray scale (or desaturate the colors), drop one of these files on a top layer of this image and 'overlay' it with the layer below.  Viola.  A simple cheat that looks much better than many digital cheats.  Add a small amount of vignetting in the corners, and now you have an interesting image with character.


And that is that.