Retouching skin is not about blurring a face flat. This workflow removes blemishes with the healing tools first, builds a Black & White plus Curves observation layer to expose the lighting problems, and then separates high and low frequencies. Every step explains why it is done, so what you take away is the reasoning, not a fixed recipe.
Step 0 – Open Online PS and duplicate the original layer
0.1 Create a project & import the image
1️⃣ Go to Online PS (zaixianps.cc).
2️⃣ Use File → Open, or drag a local image straight into the workspace.
0.2 Duplicate the original layer (keep the negative)
In the Layers panel, select the Background layer → Ctrl+J (or right-click → Duplicate) to create a Background copy layer.
Everything from here on happens on this copy; the original stays in place so nothing can be damaged by accident.
Step 1 – Blemish removal (healing tools)
1.1 Use the Spot Healing Brush
Choose the Spot Healing Brush Tool on the left of the toolbar — B.
Click or drag across the larger pimples and spots on the face; the brush samples the surrounding pixels and fills them in automatically.
1.2 Use the Healing Brush
If the skin tone varies noticeably from one patch to the next, switch to the Healing Brush:
- Alt+click to sample clean skin.
- Brush once over the blemish and the sampled color and texture are blended into the target area.
Step 2 – Lighting observation layer (Black & White + Curves)
2.1 Create an "observation" group
Click the Create a group icon at the bottom of the Layers panel and name it Observation. The layers you use to judge the lighting go in here, so you can switch them on and off at any time.
2.2 Add a Black & White adjustment layer
Menu Layer → New Adjustment Layer → Black & White (shortcut Ctrl+Alt+Shift+B), then drag this layer into the Observation group.
2.3 Add a Curves layer to boost contrast
Create another Curves adjustment layer and build an S-curve (lift the lower-left for the shadows, pull the upper-right down for the highlights) so darks get darker and lights get lighter.
Then add one more Curves layer and drag the upper-left point down slightly, which makes highlight detail easier to see.
2.4 Read the lighting
Turn on the Observation group and study how the light falls across the model:
- Green marker – shadow areas that need to be brightened.
- Red marker – highlight areas that need to be darkened.
Note these areas down; you will dodge and burn them locally on the low-frequency layer with the Mixer Brush.
Step 3 – Frequency separation (duplicate the low/high layers)
3.1 Duplicate the original layer twice more
Right-click the Background copy layer → Duplicate Layer, twice, so you end up with three identical layers.
Rename them in order:
- Low frequency (at the very bottom)
- High frequency (at the very top)
- Keep the original Background copy as a reference (hide it whenever you like)
3.2 Create the Gaussian Blur for the low-frequency layer
Turn off the visibility of the Observation group and the High frequency layer so that only Low frequency is visible.
Menu Filter → Blur → Gaussian Blur, and adjust Radius until the facial features are no longer sharp (roughly 8~12 px, depending on image resolution).
⚠️ Tip: blur too much and the high-frequency layer will drag the color detail back out with it; blur too little and the low-frequency layer keeps so much detail that the skin never really softens.
Step 4 – Mixer Brush on the low-frequency layer (local dodging and burning)
4.1 Open the Mixer Brush
Select the Low frequency layer → choose the Mixer Brush Tool in the toolbar (shortcut B; press and hold to reveal the sub-tools).
In the options bar at the top, set:
- Wet: 5%~10%
- Flow: 20%~40% (adjust to the detail in the image)
- Tick Clear each stroke
(Clear each stroke)so colors do not mix across areas.
4.2 Brighten or darken shadows and highlights locally
Following the lighting marks in the Observation group, work on the Low frequency layer with the Mixer Brush:
- Shadows → light strokes to brighten (sampling color from the brighter areas)
- Highlights → light strokes to darken (sampling color from the shadows)
The goal is even light across the whole portrait while keeping a natural sense of form.
Step 5 – Texture repair on the high-frequency layer (Healing Brush)
5.1 Leave only detail on the high-frequency layer
Turn the High frequency layer on and hide the others so that only it is visible. You will now see skin texture, pores and small blemishes.
5.2 Use the Healing Brush Tool to repair detail on the high-frequency layer
Select the Healing Brush Tool J.
Hold Alt and sample an area of fine, even-toned skin texture.
Brush lightly over the blemishes you want to fix (small spots, shine, prominent pores) and the sampled detail is copied across.
Keep in mind:
- Work on the high-frequency layer only, so the original color (low-frequency layer) is untouched.
- Move the sample point after each stroke to keep the texture distribution natural.
Step 6 – Finish and export
6.1 Toggle the helper layers and check the result
Turn off the Observation group and hide the Background copy reference layer, leaving only Low frequency + High frequency.
Toggle View → Show → Extras to make sure no selection or guide is left hidden.
6.2 Export the image
Menu File → Export As → JPEG/PNG.
JPEG at quality 90% is the recommended setting: it balances file size and detail.
Compare before and after once saved; if any area still looks unnatural, go back to the relevant layer and fine-tune it.
- Why judge the lighting first? Uneven light makes skin look dull or blotchy. Once Black & White plus Curves has made the light structure visible, you can dodge and burn precisely on the low-frequency layer, which gives a far more natural result.
- What Gaussian Blur value should I use? Usually 8~12 px for a 1080p image; for large 4K files go up to 15~20 px. The aim is to soften the facial contours without making them disappear.
- Will repairing the high-frequency layer make skin look plastic? No — as long as each sample comes from natural texture and you only work where it is needed, the skin keeps its original fine grain.
- What happens if the Mixer Brush wetness is too high? It drags the low-frequency color straight along the brush path and turns the skin into flat patches. Stay at 5%~10%.
References
- Adobe Photoshop official documentation
- HTML5 and the principles of modern front-end image processing
- Online PS