The problem with Lightroom skin softening adjustment is that the end result is plastic-like finish. In this article we will summarize Scott Kelby's Photoshop (Ps) process in his latest book: "Photoshop for Lightroom Users (Voices That Matter)".
Step 1: Select the photo
Select the photo you want to work on from Lightroom Library. You can use Lr Spot Removal tool to remove big blemishes by going to the Develop Module (D).
Step 2: Open the photo in PS
Open the image in Adobe Photoshop - Apple Cmd+E / PC Ctrl+E. If prompted to Render using Lr select that button.
Step 3: Duplicate the background layer
When Photoshop opens with your background layer as the original photo, duplicate the layer by pressing Apple Cmd+J / PC Ctrl+J. By duplicating the layer you will be working in a non-destructive model and you will have the option to see the before and after of your adjustments.
Step 4: Apply High Pass Filter
In Ps go Menu - Filter - Blur - Other - High Pass. Enter 24 pixels in the dialog box under Radius. 24 pixels works fine for this tightly cropped photo. If the face of your portrait is more tightly cropped, use 18 pixels instead. Press OK and the photo will turn mostly gray. Don't worry, that's OK. (Figure.2.)
Step 5: Apply Gaussian Blur Filter
In Ps go Menu - Filter - Blur - Gaussian Blur. In the radius field enter a number that is the third of the number you entered in the High Pass filer. So 18/3=6. Click OK to apply the Gaussian Blur filter as in figure.3.
Step 6: Invert the Image
Next, we are going to invert this layer by going under Menu - Image - Adjustments - Invert. If you prefer shortcuts that's Apple Cmd+I / PC Ctrl+I. At this point, the photo still looks bad to say the least but don't worry, we are getting there. We are going to change the layer blending mode so that we get rid of the gray. For that go to the layer panel and under blending drop down list select Linear Light as in figure.4.
Step 7: Blending Options
To get rid of the halo effect, go to the bottom of the layer panel and select Layer Style (represented by a small fx button - the second one from the left) and select Blending Options. In the "Blend If" option (figure.5.) Apple Cmd / PC Alt +Click and drag the upper slider (This Layer) all the way to the left as seen in figure .6.
Click OK and the result is what we are going to use for softening the skin (figure.7.)
Step 8: Add a layer mask and reveal the skin only
What we are seeing in figure.7. is what we are going to use for skin texture. However, the effect is also appearing over the details: eyes, lips, nostrils, eyebrows, nostrils, etc. So we need to hide this layer from view by applying a layer mask. To do that, Apple Option / PC Alt + click on the Add Layer Mask icon on the bottom of the layer panel. This is the third icon from the left of the layer panel. This will hide all because the mask in black. Now we need to reveal and for that we should choose a white brush. So D to set the foreground color to white, get the brush tool (B), and in the brush picker in the option bar select a medium sized, soft edged brush and set its Opacity to 100%.
Paint over just the skin areas avoiding all the details like the eyes, lips, etc. Also avoid the edges of the face as they will appear softer and we don't want that...Figure.8.
Notice how your brush is smoothing and removing all splotchy areas of the skin. This is really enhancing the texture of the skin as you paint. Wonderful isn't it?
Step 9: Lower the effect of the softening as needed
At this point you have applied the technique at full power (brush opacity at 100%). That is probably too much. To lower the effect, lower the layer Opacity to around 50%. It depends on the person and their skin but in all cases don't go above 70%.