How to Retouch Skin in Portraits Using Frequency Separation

Portrait photographers strive to achieve beautiful skin in their images; skin that is realistic and preserves natural texture. Expertly applied makeup and good lighting are the foundation for beautiful skin, but careful retouching is the finishing polish. 

In this tutorial, you'll learn three great techniques for retouching skin in Adobe Photoshop, and find out which situations benefit from each technique. Then you'll learn two quick tips that you can apply with all three techniques. Watch the video below from Abby Esparza's Photoshop course to learn all about the frequency separation method of skin retouching, or follow along with the instructions below.

Because we’ll be comparing three techniques, the Photoshop instructions in this tutorial are brief. If you need help with using the Photoshop tools, have a look at our four-part series, The Secrets of Photoshop’s Retouching Tools.

1. Add a Touch-Up Layer

In retouching, a simple process will often achieve what you need, and this holds true when retouching skin. Using a touch-up layer is a simple way to deal with blemishes, marks, and spots. It also works well to remove flakes of makeup, lint or dust, as well as tiny strands of hair or, indeed, any rogue hair popping out where it's not wanted. I also use a touch-up layer to retouch makeup when it’s needed; for example, to clean up lipstick that’s bled into the surrounding skin, or to fill in gaps in eyeliner to get a nice, clean line.

A touch-up layer does not work well for retouching patches of skin, blotchy skin, or hot spots. It is also not the right technique for dealing with multiple tiny blemishes. Limit touch-up layers to retouching noticeable problems that are surrounded by unblemished skin.

Step 1

To use a touch-up layer, start with your background layer in Photoshop and add an empty layer on top. 

Step 2

Set your tools. To do your touch-ups, you will switch between the Clone Stamp and the Healing Brush. I will sometimes use the Spot Healing Brush as well, if the area I’m working on is fairly uniform. When using the Healing Brushes, be sure that the tool option Sample All Layers is checked. When using the Clone Stamp, you will want to ensure that the tool option for Sample is set to Current & Below. With all three tools, I like to start with a small brush at 50% to 75% hardness. A softer brush tends to result in an artificial softness to the touch-ups.

Step 3

Begin with the Healing Brush. Select your new empty layer, zoom in, and set your brush size just slightly larger than the blemish. Sample skin in a clean area as close as possible to the blemish you are retouching. Pay attention to how the skin texture flows (for example, sideways on a forehead) and where skin tone changes. You will get the best results if your sample is as similar as possible to the area you are retouching.

Place your brush over the top of the blemish and just click. Don’t sweep, paint, or make several clicks on top of each other. Move around the face, clicking away the obvious blemishes. Resample as you move over different areas of the face.

Step 4

Some touch-ups will work best with the Clone Stamp tool; for example, cleaning up makeup lines or removing long, fine strands of hair. To touch up with the Clone Stamp, set your cloning tool at 20% opacity, sample as close as possible to the area you are touching up, and click or paint away what needs correcting.

Step 5 

The touch-up layer can work well for some wrinkles. If your subject has fine, blemish-free skin and you just want to lighten a few wrinkles, try using the Clone Stamp tool. You will achieve a natural looking result if you touch up the wrinkles a bit more than you want, then lower the opacity of the touch-up layer just until the wrinkles below show enough to bring back texture and restore a natural look.

Step 6

Be adventurous with a touch-up layer; the beauty of this technique is its flexibility. If you’re not happy with a touch-up, simply select your Eraser, erase the correction off the touch-up layer, and start again. If the touch-up is a bit heavy, use your Eraser at a low opacity with a very soft brush and just wipe some of the correction away. You can also reduce the opacity of the touch-up layer, or use a layer mask if you find that helps blend in the touch-ups.

For some photographs, this is as far as you need to go to achieve beautiful skin. Sometimes, however, you will need to do more. Whether you do more or not, I recommend always starting with a touch-up layer. Any further retouching you do will be easier and more effective if you’ve done those touch-ups first.

2. Frequency Separation

When more is needed to achieve beautiful skin, frequency separation is an option. The steps to create the working layers are technical, but the reward is an ability to do touch-ups without harming or losing skin texture.

Frequency separation works well for tiny blemishes, blotchy skin, red patches, wrinkles of all types, dry and flaky skin, and oily patches. This technique does miracles with under-eye circles and is also ideal for smoothing out makeup that has caked or has not blended well. I have also used frequency separation to smooth out wrinkles in a backdrop and to soften the blend between two images in a composite. Frequency separation is not good for removing stray hairs, removing blemishes that are clearly defined, or doing a general, overall skin touch-up. 

Some hot spots can be removed with frequency separation. If the hot spot is mild to moderate and there is visible skin texture over the hot spot, then frequency separation will help and, often, resolve the problem. If, however, the hot spot is blown out and skin texture is not visible, using frequency separation will result in patches that look heavily made-up.

Step 7

Create a new merged layer—Stamp Visible—of the work you’ve done on your portrait so far. Ensure your Background and Touch-Up layers are turned on (visible), select both layers, then while holding down the Option (Alt) key, choose Layer > Merge Visible from the Layers panel menu.

Step 8

Make two copies of the newly merged layer and label the top copy “High Frequency” and the middle copy “Low Frequency.” Turn off the High Frequency layer and select the Low Frequency layer. This layer contains all the colour information. Blur that layer by using Filter > Blur > Gaussian Blur. You want to blur the layer until the pore detail at 100% is gone in the skin—usually a blur of 2 pixels or less. 

Step 9

Select the High Frequency layer and turn it back on. Go to Image > Apply Image, and apply the settings shown in the following image. Change the layer’s blending mode to Linear Light.

Step 10

Next, add a new empty layer above the Low Frequency layer, and move the Merged layer from the middle of the layers to the top (above High Frequency). Turn off the Merged layer. It’s there for you to turn on and off when you need to see the before and after to assess the changes you’ve made.

Step 10

Click on the empty layer above the Low Frequency layer and select your Clone Stamp tool. Use a soft brush at 25 or 50% hardness with opacity at 15 to 20%. Ensure the Sample selection for your tool is Current & Below. 

Select your sample area and work in small stages with the Clone Stamp tool to blend and correct the areas that need attention. It’s tempting and easy to pursue perfect skin, leaving behind memories of what the person really looked like. That’s why I move the Merged layer to the top and turn it on and off to check my progress.

As you work, pay particular attention to changes in shading on the face and natural contours. It’s easy to inadvertently spread a highlight too far or to clone slightly darker skin into lighter areas. Spreading a changed skin tone too far will change the shape of the person’s face and destroy the shadows and highlights you carefully sculpted with your lighting during the shoot. Beware, too, that you don’t blend the natural shading so much that there is no change in skin tone and thus no shape left.

Step 11

When you’re happy with that work, switch to the High Frequency layer. This layer contains all the texture. You can use either the Clone Stamp tool or the Patch tool on this layer. If using the Clone Stamp tool, you will need to increase the brush opacity to 70 to 100% and soften it to 25%. Select an area with even texture as the sample for your cloning and correct large pores, fine chin hairs, and anything else that needs attention. 

You may find that the Patch tool is more effective for dealing with deep wrinkles. Select a wrinkle or part of a wrinkle and move it to a nearby patch of evenly textured skin. Go lightly with these touch-ups and use caution: you want to reduce wrinkles and minimize pores, not eliminate them.

Step 12

Before you finish with frequency separation, try this trick as a subtle alternative to sharpening: 

• Duplicate the High Frequency layer, mask out the whole layer (hold Option or select Alt + Add a Mask from the Layers palette). 

• Select the mask and a medium, soft brush. Using white, paint in the areas on the mask where you would like sharpening applied. I like to paint in eyes, lips, jewellery, and hair.

3. The “byRo” Touch-up Method

Sometimes, skin needs an overall touch-up. It could be in addition to the other two techniques we’ve looked at or in place of frequency separation. The byRo Method, named after the retoucher who invented it, is particularly effective for quick, overall smoothing that retains skin texture. Like frequency separation, the byRo Method is very technical to set up, but the reward is worth the effort.

I like to use this technique for smoothing out poorly applied foundation makeup, evening out skin tone, or correcting skin with large pores or patches of small breakouts. The byRo Method is also ideal when the subject has beautiful skin, hasn’t worn makeup, and needs just that tiny bit of evening out. Consider this technique, too, when the camera lens is so sharp and clear as to be cruel. (My favourite portrait lens, for example, is a 100mm macro lens, but it is so sharp and clear that I usually have to adjust for it in post-processing.) I also use the byRo Method in combination with a bit of brightening with Levels to lift the tired look people tend to have when they skip too many vacations or have suffered an illness. 

The byRo Method is not good for dealing with noticeable blemishes, blotchy skin, or red patches. Blemishes are better handled with a touch-up layer, and red patches respond well to frequency separation. For blotchy skin, check out the Tuts+ tutorial, Minimizing Red Blotches on the Skin in Post-Production.

Step 13

To get started with the byRo Method, create a new Stamped Layer as you did for Frequency Separation. Duplicate that layer. 

Step 14

Select the duplicated layer, and in the Filter menu, choose Blur > Gaussian Blur. You will not be applying this blur; you are using this step to determine the settings you will need further on. Adjust the radius in the Gaussian Blur dialogue box until the skin smooths out and any variation in skin tone goes away. Note the radius you selected and then Cancel the dialogue to finish without applying the blur.

Step 15

Return to the Filter menu, and choose Other > High Pass. In the High Pass dialogue box, enter the radius you selected when testing the Gaussian Blur in the previous step. Apply the High Pass filter.

Step 16

Still working on the same layer, go back to the Filter menu again to apply a Gaussian Blur to the High Pass layer. This time, your radius will be about one-third of whatever radius you used for the High Pass filter. For example, if your setting for the High Pass filter was a radius of 9 pixels, use a radius of 3 pixels for the Gaussian Blur.

Step 17

Next, invert the High Pass layer. (Under the Image menu, select Adjustments > Invert.) Change the layer blending mode to Linear Light. Lower the opacity of the layer to 40 to 50%. 

Step 18

Mask out the whole layer (Option or Alt + Add a Mask from the Layers palette) and select a small to medium, soft brush. Set the brush opacity to 50% and the colour to white, and begin to paint in skin that needs smoothing. Do not paint in areas with details, such as eyes, nose, hair, and lips. Also, do not paint in around the edge of the face.

Step 19

Continue painting in the mask until you’ve achieved the desired amount of softening where you want it. You can lower the effect by changing the opacity of the brush as you paint in different areas of the face, or by lowering the opacity of the whole layer. If you’ve smoothed an area of skin more than you intended, switch your brush to black and paint the correction back out.

In this portrait, the model had large areas of small blemishes. Otherwise, her skin needed little touch-up, so I used just the Touch-Up Layer and the byRo Method. I didn’t bother with Frequency Separation.

Final Touches

Regardless of the touch-up techniques you use to achieve beautiful skin, consider these two final steps to finish your work.

Hue Adjustment

Digital photography seems to emphasize reds in skin tone and over-saturate all colours. We’ve grown accustomed to the look of digital photographs, but the reds and over-saturation will ruin a fine portrait with corrected skin. To adjust this, apply a Hue Adjustment layer.

• Select Reds and nudge the Hue to the right just until you see the red tones settle down (usually about +1 to +3).

• Select Yellows and nudge the Saturation down until the skin tone looks more natural (usually between -5 and -10).

• Select Master (all colours) and lower the Saturation down a tiny bit, watching just for that over saturated look to ease a bit (usually between -1 and -7).

Adjusting skin colour by eye takes practice, especially if you are working on a skin tone or colour unfamiliar to you. The Hue Adjustment layer can be revisited and tweaked, so don’t be afraid to play with settings until you are able to get skin that looks natural and healthy.

Add Grain

Digital photography combined with better and higher-resolution monitors provides us with images that are unnaturally smooth and clean. Even when we’ve preserved skin texture in retouching, digital photography minimizes it with smooth perfection. To help restore some texture and depth to skin, add a layer of grain.

• Under the Layer menu, choose New > Layer and put in the settings in the image below.

• Select the new Grain layer and under the Filter menu, choose Filter Gallery > Grain. Set the Intensity and Contrast both to 30 and choose Enlarged grain mode. Apply those settings. 

• Now desaturate the Grain layer by going to the Image menu and choosing Adjustments > Desaturate. 

• Adjust the layer opacity to taste (usually between 40 and 50%).

Conclusion

And there you have it: three techniques to help you achieve beautiful, natural-looking skin in retouching. A Touch-Up Layer will help you deal with noticeable blemishes and spots. Frequency Separation will help you correct a number of issues while still preserving skin texture. And byRo’s Method will give you an opportunity to do some overall smoothing and brightening. Use one or two or all three techniques as needed, but consider always starting with a Touch-Up Layer to make the rest of your touch-up work easier and more effective.

If you want to finish your work with an overall refined feeling, consider adjusting the Hue and Saturation of your image, paying particular attention to the Reds and Yellows. Adding a layer of grain as the final layer will add depth and realism to the whole image.

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