Frequency separation splits an image into high-frequency details (skin texture, fine hairs, pores) and low-frequency tones (color, shading, gradients) for independent retouching in Adobe Photoshop.
Frequency Separation Setup in Photoshop
Duplicate the base image layer twice. Perform the following on each layer:
Low Frequency (Color / Tone Layer)
- Rename layer to Low Frequency (or Color/Tone).
- Apply Filter → Blur → Gaussian Blur... (typically 2 to 8 px depending on image resolution, until fine skin pores blur away).
High Frequency (Texture Layer)
- Rename layer to High Frequency (or Texture).
- Change layer blend mode to Linear Light.
- Go to Image → Apply Image...:
- Layer: (Select the Low Frequency layer)
- Blending:
Subtract - Scale:
2 - Offset:
128