Take any photo and open in Photoshop.
Next, you needed create new alpha layer. Shift + Command (or Control) + N.
After that, fill layer 50% gray. Shift + F5.
It's must look like that.
Next, go in Filters — Texture — Grain. Check what gray layer selected.
Take the same value of properties.
Stand by on gray layer and make monochromatic grain, go Image — Adjustments — Desaturate. Shift + Command (or Control) + U
Select "Soft light" in Blending mode.
For improve result, duplicate grain layer.