Smoothing Skin with Luminosity

Topics covered in this Photoshop tutorial:

The Channel Mixer adjustment, Using Channels to smooth skin tones, The Luminosity blending mode

Exercise Preview

Exercise Overview

Experienced photographers know that the Red channel often contains the smoothest skin texture. We can take advantage of this in Photoshop by using the Channel Mixer set to Luminosity to blend in the smoother tone.

Looking at One Image

1. Open yourname-WhiteShawlWoman.psd if it isn’t still open.

2. Hide the smooth skin layer group.

3. Select the Background layer.

4. Look at each color channel (one channel at a time) by pressing Cmd–3, 4, 5 (Mac) or Ctrl–3, 4, 5 (Windows).

   Although the Red channel shows the smoothest skin (i.e. least variation in red content), her forehead still shows texture on all channels. Photographers who shoot in black and white know they can take advantage of the uniformity of red content in skin to smooth its appearance by using a yellow, orange, or even red filter to increase the amount of tonal information from the red component recorded on film, and hiding the more texture-laden green and blue components.

   You can take advantage of this same technique in color portraits by a similar technique: replacing the luminosity from the Green and Blue channels with that of the Red channel. Because this image contains undesirable skin texture even on the Red channel, it’s not well suited for this technique, so let’s try an image that is.

Smoothing the Skin in a More Suitable Image

1. Close this file without saving changes.
2. From the Photoshop Adv Class folder, open PinkTankTopGirl.psd.
3. Save it as yourname-PinkTankTopGirl.psd.
4. Go to the Channels panel and take a close look at the skin texture on each of the three color channels. The blotchiness is almost completely absent on the Red channel. We’ll use the Red channel’s smooth tonality to replace the undesirable texture on the other two channels.
5. Select the composite RGB channel.
6. Choose the Lasso tool and make a rough selection of the woman’s face.
7. Go to Select > Select and Mask.
8. In the Properties panel on the right, click on the thumbnail to the right of View and double–click On White.
9. Set Opacity to 100%.
10. In the Global Refinements section, give it a few pixels Feather as needed.
11. Click OK. We’ll fix the eyes, eyebrows, mouth, hair, etc. later.
12. Choose Layer > New Adjustment Layer > Channel Mixer.
13. Name it smooth face and set the blending mode to Luminosity. This ensures that no color shifts will take place; only luminosity (light/dark) will be affected.
14. Click OK.
15. In the Properties panel, check on Monochrome.

16. Set the channels as follows:

    Red:	100%
    Green:	0%
    Blue:	0%

    (The Total at the bottom should read 100%.)

17. You’ll see the face get smoother as well as lighter. Often this technique will produce the desired texture, but the skin looks too light and flat. Don’t worry; you’ll fix it in a moment. But first, if the edges of the selection show up and don’t look desirable, paint with a soft brush on the Layer Mask of the smooth face layer so the edges blend nicely.
18. Next, with the layer mask still selected, paint with black over the eyes, eyebrows, mouth, hair, and overexposed highlights so that only the skin is being smoothed.
19. Let’s fix the contrast and darkness of her face. Make sure the smooth face layer is selected.

20. Choose Layer > New Adjustment Layer > Curves and set the following:

    • Name it face brightness & contrast
    • Check on Use Previous Layer to Create Clipping Mask.
    • Set Mode to Luminosity.
    • Click OK.

21. As shown below, adjust the curve to add some contrast and lighten the face:

    

22. Save this image and close it.