Give your work a textured, organic feel with a nice grainy noise layer.
Noise layers randomize the brightness and colors or pixels to add a more natural texture to your digital work.
From the Filter tap Custom Noise.

Custom Noise Presets

The following presets are available for custom noise.
Clouds, Flames, Earth, Sand, Rain, Wood Grain, Sketch, Watercolor Paper 1, Watercolor Paper 2, Watercolor Paper 3, Marker Paper 1, Marker Paper 2

Custom Noise Settings

Blending Mode: Select from any of blending modes to control how the noise layer appears on the canvas.

Color 1 and Color 2: Change the colors here.

Opacity: Decreases or increases transparency of the filter.

X: Controls the horizontal slant of the noise filter.

Y: Controls the vertical slant of the noise filter.

Angle: Controls which angle the noise filter is tilted towards.

Octave: Adjusts how fine the grain of the noise is.

Persistence: Adjust the size of the noise grain and its patterns.

Cutoff: Adjusts or increases the presence of the secondary color.

Gamma: Adjusts or increases the opacity of the primary color.

Offset: Adjusts the saturation of the primary color.