Artificial Film Grain Effect.

First you start off by making the image black and white. Then I added another empty layer and called it grain for future reference.

You need to fill this layer with 50% grey. You do this by going to edit>fill then selecting '50% grey' on the dropdown menu. The layer then needs to be set to overlay.

On the 'Grain' layer you need to then go to filter>noise>add noise and the pop up window should appear. Make sure you have 'monochrome' ticked as this will only add black and white grain. If you go too overboard you can easily turn the layer opacity down.

This effect was inspired by Tony Ray Jones' work and using fast film in his images to enable him to use faster shutter speeds.
Here are a couple examples of his work

The effect on my image isn't quite as strong as in these images, but these images do have a slightly softer look to them being shot on film.