How to discreetly and efficiently remove defects from the skin, but preserve the texture? How to accurately align the pigment and unevenness of the face? For such tasks, simple tools like a stamp or a healing brush will not be enough. You will need frequency decomposition.
We will tell you what frequency decomposition retouching is, how to do it efficiently, quickly and at the same time not turn your face into a plastic mask.
What is frequency decomposition in Photoshop
Frequency decomposition retouching is when a photo is decomposed into several frequencies using a special algorithm. Usually the picture is divided into two frequencies — upper and lower.
The upper frequency is responsible for the details and texture. These include pimples, wrinkles, small scars, moles, individual hairs, black dots, dust, crumbling mascara. The lower frequencies are the cut-off pattern and color. They are responsible for the shape, large elements of the picture.
Having decomposed the photo into two frequencies, the photographer works separately with fine texture and chiaroscuro. This allows you to gently smooth the skin, but leave pores; remove pimples, but keep the color intact.
How to do frequency decomposition
In frequency decomposition skin retouching, it is incredibly important to follow the exact procedure, not to skip any of the steps. Initially, it seems difficult, but after 5–10 repetitions with an outline at hand, the process is remembered.
The algorithm needs to be learned — this is inevitable. But you get an incredibly powerful and fast way to retouch the skin, which will speed up processing and bring it to a new level.
Stages of frequency decomposition. Layer preparation
1. Make two copies of the original layer.
To do this, right-click and click Duplicate Layer / Duplicate Layer. Faster option — keyboard shortcut Ctrl+J. You need to do this twice. The top layer will be for high frequencies, textures, the bottom one — for low frequencies — chiaroscuro.
2. Develop low frequencies.
— Turn off the visibility of the high frequencies layer — click on the eye icon to the left of the layer.
– Click on the layer with low frequencies.
— Apply a filter to it Blur Gaussian / Guassian Blur.
You can find it at the top of the menu. Filter / Filter — Blur / Blur — Gaussian Blur / Guassian Blur.
– Select the blur radius.
The larger the face in the frame, the larger the radius value. Usually this range is from 3 to 20 pixels. Blur group and full-length portraits, where the faces of the models are small, blur by about 3–5 pixels, and portraits, where the entire space of the photo is occupied by the face, by 15–20 pixels. These numbers are not an axiom, but a convenient starting point for your own experiments.
3. Develop high frequencies.
– Turn on the visibility of the high frequency layer.
‑Place on the layer with high frequencies by clicking on it with the left mouse button.
– Open Image / Image — External Channel / Apply Image.
Here we will “pull out” the texture on the layer with high frequencies. To do this, a blurry layer with low frequencies is subtracted from the source.
Only one thing is important here — set the following settings:
- in the tab Layer / Layer select the low-frequency layer you blurred (another reason it’s good for a beginner to rename layers).
- For 8‑bit mode: Overlay / Blending — Subtraction / Subtract. Scale / Scale — 2. Shift / Offset — 128.
If the image turns grey, don’t worry! So be it. So you are on the right track.
- For 16-bit mode: Overlay / Blending — Adding / Add. Scale / Scale — 2. Shift / Offset - 0. check mark Invert / Invert.
– Press OK or key Enterto apply the settings.
— Put the gray layer with high frequencies in overlay mode Linear Light / Linear Light.
Frequency Decomposition — Instrument Settings
In frequency decomposition, work goes on alternately with two frequencies. You can constantly switch between layers, or retouch in stages — first, a complete cleaning of pimples, hairs, and then editing chiaroscuro. The order is not fundamental. It is important not to confuse the tools and layers on which you are working.
For retouching, we will use the tools Clone Stamp Tool, Healing Brush Tool and Mixer Brush Tool. Read more about how these tools work in the text about basic retouching.
Treble instrument settings
On the texture retouching layer (pimples, wrinkles, scars, hair), you can work with two tools:
- Stamp / Clone Stamp Tool.
- Healing Brush / Healing Brush Tool.
The main thing, as well as for stamp- in the dropdown list Sample / Sample choose Current Layer / Current Layer.
This is necessary in order for the tool to take a patch from the layer on which it is located, without using the layers below it. Otherwise, the patch will be strongly knocked out in color. Otherwise, you can leave the default settings.
Secrets of frequency decomposition: working on a layer with high frequencies
- The size of the brush should match or be slightly larger than the defect.
You don’t need to measure the brush radius pixel by pixel to match the pimple or hair thickness, but it’s also harder to work neatly if the patch is much larger than the flaw.
- Look for areas with similar textures to patch.
Skin has different textures on different parts of the face. For example, the skin under the eyes is more delicate and thin than on the cheeks. Visually, the skin on the forehead and on the nose also differ from each other. To make the retouching invisible, look for a patch nearby. If you are retouching the cheek, sample the stamp or repair brush from the cheek as well.
- Take patches from areas with the same brightness.
For example, if you try to transfer a patch that you took from a skin area in the shadow to a highlight, a discrepancy in textures will catch your eye.
Instrument settings for low frequencies
To even out chiaroscuro, smooth out age spots, you need to stand on a layer with low frequencies and use the tool Mixer Brush Tool.
Mixer Brush Tool is an attempt by the developers of Photoshop to mimic the effect of a regular brush in reality when an artist paints on paper. It transfers color from one area of the picture to another in strokes, and also mixes colors together, as if you were trying to mix two colors on a palette.
Principles of working with a mix brush in frequency decomposition
If the complexion needs to be smoothed out, move the brush in small circular motions. This way the colors will blend.
If the task is to correct or extend the shadow, slightly lighten the bruises under the eyes, then you need to work with strokes, transferring the color from one part of the picture to another.
The mix brush is a powerful tool with which you can easily “kill” the anatomy of the face. For example, it should be remembered that the most convex parts of the face (forehead, nose tip, chin, nose column, cheekbones) should be lighter than everything else. Shadows lie under the cheekbones, under the lower lip, under the jaw.
Another secret — in no case should you completely remove the nasolabial fold. To avoid this, constantly look at the chiaroscuro source. This will help you notice unnaturalness in time and go back a couple of steps.
Life hack: if you did something wrong, undo the last commands using the keyboard shortcut Ctrl + Z.
After retouching by frequency decomposition, the result may seem too strong — the skin in such cases seems “plastic”, too smooth. In this case, add layers to the group (illustration below) and lower the opacity of the resulting folder. Then the natural texture will show through the retouching. With practice, you will resort to this less and less — learn how to carefully retouch without overdoing it.