Here's a step-by-step guide on how to do Frequency Separation Portrait Retouching in Photoshop:
1. Duplicate Your Base Layer (Background Layer):
* Right-click on the "Background" layer in the Layers panel.
* Select "Duplicate Layer."
* Rename the new layer to something like "Low Frequency" or "Color/Tone."
* Right-click on the "Background" layer again.
* Select "Duplicate Layer."
* Rename this layer to something like "High Frequency" or "Texture."
2. Prepare the Low Frequency Layer (Color/Tone):
* Select the "Low Frequency" layer.
* Go to Filter > Blur > Gaussian Blur.
* Adjust the Radius until the skin texture is blurred, and you can no longer see fine details like pores. You want the color transitions to be smooth. Don't overblur; you just want to blend the color information. A radius between 4-8 pixels is a good starting point, but it depends on the image resolution and the amount of visible texture.
* Click OK.
3. Prepare the High Frequency Layer (Texture):
* Select the "High Frequency" layer.
* Go to Image > Apply Image. This will essentially subtract the blurred "Low Frequency" layer from the "High Frequency" layer, leaving only the texture.
* Layer: Choose the "Low Frequency" layer.
* Blending: Choose "Subtract."
* Scale: Enter "2."
* Offset: Enter "128."
* Invert: Make sure this is NOT checked.
* Channel: Usually, you will leave this on RGB. If you are having issues (e.g., weird colors), try experimenting with the different channels.
* Click OK.
* Change the Blending Mode of the "High Frequency" layer to "Linear Light." This will make the texture details visible again.
4. Retouching the Low Frequency Layer (Color/Tone):
* Select the "Low Frequency" layer.
* Use the Mixer Brush Tool (B) or the Blur Tool (R) to smooth out color and tone variations.
* Mixer Brush Tool: This is generally preferred because it blends the colors more naturally. Set your settings:
* Clean the brush after each stroke: Checked
* Sample All Layers: Checked
* Wet: Adjust this to control the intensity of the blending. A lower value is usually better for beginners (around 10-20%).
* Load: 1%
* Mix: 90%
* Flow: 5-15%
* Size: Adjust the brush size according to the area you're working on.
* Blur Tool: If using the blur tool:
* Strength: Keep it low (5-15%)
* Mode: Normal
* Technique: Use small, circular or stroke-like motions to blend the colors. Follow the natural contours of the face. Focus on removing blemishes, evening out skin tones, and smoothing out shadows.
* Zoom in and out frequently to check your work. It's easy to overdo it.
5. Retouching the High Frequency Layer (Texture):
* Select the "High Frequency" layer.
* Use the Clone Stamp Tool (S) or the Healing Brush Tool (J) to remove blemishes and unwanted textures. It's crucial to use these subtly.
* Clone Stamp Tool: Set your settings:
* Opacity: Keep it low (around 10-20%)
* Flow: Keep it low (around 10-20%)
* Sample: Current Layer
* Aligned: Check the Aligned box to ensure that your source point follows your cursor as you paint. Uncheck it to copy from the same spot each time.
* Healing Brush Tool: Set your settings:
* Type: Normal or Replace
* Source: Sampled (make sure it is sampled!)
* Sample: Current Layer
* Aligned: Check the Aligned box to ensure that your source point follows your cursor as you paint. Uncheck it to copy from the same spot each time.
* Diffusion: (Adjust according to your needs).
* Technique: Sample from areas near the blemish or unwanted texture to maintain the natural skin texture. Use small brush sizes and low opacity/flow to avoid creating noticeable patches. Focus on imperfections, being careful not to remove too much natural texture.
* Zoom in and out to check your work. Over-retouching texture is a common mistake.
6. Fine-Tune (Optional):
* Adjust Opacity: If either the "High Frequency" or "Low Frequency" layer looks too strong, adjust its opacity to blend it more seamlessly with the rest of the image.
* Create Adjustment Layers: Add adjustment layers (e.g., Curves, Levels, Color Balance) to fine-tune the overall color and tone of the image. Apply these *above* the frequency separation layers. You can also use a luminosity mask to target specific tonal ranges.
* Sharpen: If needed, you can add a subtle sharpening effect to the final image. Be careful not to over-sharpen, as this can accentuate texture irregularities.
* Reduce Noise: If you have a noisy image, you can use noise reduction techniques *before* frequency separation.
Tips and Best Practices:
* Non-Destructive Editing: Always work on duplicates of your original layer. Consider using Smart Objects for more flexibility.
* Subtlety is Key: The goal is to enhance the portrait naturally, not to create a plastic or artificial look. Less is often more.
* Practice: Frequency Separation takes practice to master. Experiment with different settings and techniques to find what works best for you.
* Understand Your Image: Different images require different settings. Adjust the Gaussian Blur radius, Mixer Brush settings, and Clone Stamp opacity based on the specific image and the amount of retouching needed.
* Avoid Over-Smoothing: Over-smoothing the Low Frequency layer can result in a loss of dimension and a flat appearance.
* Preserve Key Details: Don't remove natural features like freckles or beauty marks unless specifically requested. These add character to the portrait.
* Dodge and Burn: After frequency separation, consider using dodging and burning to further refine the light and shadows on the face and body.
* Use Masks: For localized adjustments, use layer masks to target specific areas of the image.
Troubleshooting:
* Weird Colors or Artifacts: If you see strange colors or artifacts, double-check that you used the correct settings in the Apply Image dialog (especially "Subtract," "Scale," and "Offset"). Experiment with the channel in Apply Image.
* Texture Looks Too Uniform: You may have over-retouched the High Frequency layer. Reduce the opacity of the layer or use a layer mask to selectively remove the texture.
* Skin Looks Flat: You may have over-smoothed the Low Frequency layer. Reduce the opacity of the layer or use a layer mask to selectively restore some of the original texture.
* Image Looks Blurry: You may have used too much Gaussian Blur on the Low Frequency layer. Reduce the blur radius.
By following these steps and practicing regularly, you can master the Frequency Separation technique and achieve professional-looking portrait retouching results. Remember to always prioritize a natural and realistic outcome. Good luck!