Frequency Separation in GIMP – Skin Smoothing Tutorial

In this video we will be learning how to even out the skin tone and make it smooth by using the technique of Frequency Separation in GIMP.

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Video Summary

This detailed tutorial from Creative Pad Media covers the advanced technique of Frequency Separation in GIMP, used to achieve smooth skin while preserving natural texture in portrait photography.

The Concept of Frequency Separation

Standard blurring or smudging makes skin look plastic because it destroys texture [03:52]. Frequency separation solves this by splitting the image into two layers:

1. Color and Tone (Low Frequency): Handles the colors and transitions between highlights and shadows [04:37].
2. Texture (High Frequency): Handles fine details like pores, hairs, and imperfections [04:43].

Step-by-Step Workflow in GIMP

1. Preparation: Duplicate your original layer twice. Name the bottom one “Color and Tone” and the top one “Texture” [05:09].
2. Setup “Color and Tone”: Apply a Gaussian Blur to this layer. Increase the blur just enough so that the fine skin texture disappears but the overall colors remain [06:03].
3. Setup “Texture”: * Change the blending mode of the Texture layer (which is still a sharp copy) to Grain Extract [08:07].
   • Right-click the layer and select “New from Visible” to create a dedicated gray texture layer [09:04].
   • Reset the blending mode of your “Color and Tone” layer back to Normal [09:34].
   • Change the blending mode of the new Texture layer to Grain Merge [10:16].
4. The Retouching Process:
   • Smooth Tones: Select the “Color and Tone” layer. Use the Free Select Tool (with feathered edges) to select areas of the skin, then apply Gaussian Blur within the selection [12:35, 14:11].
   • Shortcut: Use Ctrl+F to repeat the last blur filter on a new selection [16:16].

Professional Tips

• Feathering: Always set your selection tool to have a high Feather Radius (e.g., 40px) to ensure the blurred areas blend naturally into the rest of the skin [14:29].
• Group and Refine: Place both FS layers in a Layer Group. You can then lower the Opacity of the entire group if the effect looks too “fake” or use a Layer Mask to hide the effect in specific areas [23:04, 24:51].
• Specular Highlights: Pay special attention to the nose and forehead, as spreading out strong highlights creates the appearance of using professional studio lighting [18:15, 19:07].