Grain
Adding simulated film grain to give your photograph a gritty look.
- Select
- Set the color to (128, 128, 128)

- Right click on the layer mask and select Delete Layer Mask

- Set Blend mode to Overlay

- Select
- Set Distribution to Gaussian and check Monochrome. Set Amount.

- Adjust the opacity of the noise layer.
Sample photograph
After Gorman conversion and Levels adjustment...
With grain...