While changing the appearance of skin is something Photoshop is renowned for, doing it the first time requires a bit of practice and some patience. Photoshop provides several methods for changing skin color, but not every technique works perfectly with every photo. Whether you want to remove a few blotches or give your model a complete makeover, use layers to experiment with adjustments, hue and saturation, levels and painting without damaging the original image. Make good use of the Opacity slider on the layers to blend the effects into the original image.
Focusing on Skin Color Alone
Making changes to skin color can have strange effects on the rest of the photo if you don't first isolate the skin. Use the Lasso tool or one of the other selection tools in the toolbar to outline the skin you want to change. To create multiple lassos, hold down the Shift key after completing each lasso. In most cases, you will want to use a sufficient feather -- located in the Options bar -- so the color change isn't abrupt. An appropriate amount of feathering can vary from 2 to 4 pixels for a low-resolution 50K file up to 60 or 80 pixels for a high-resolution image.
Selective Color Adjustment
After selecting the area of skin you want to change, tap the “Selective Color” icon in the Adjustments panel or select “Selective Color” from the fly-out menu on the panel to add an adjustment layer to the document. Choose "Reds" or "Neutrals" from the Color menu and then drag the color sliders as needed to make the changes you want. Dragging the "Magenta" slider to the left makes skin less pink, for example, while dragging it to the right increases pinkness. Even with feathering, the slightest change in color may look look blotchy around the edge of the lasso. If this happens, reduce the layer's opacity in the Layers panel, starting at around 80 percent.
Photoshop Body Paint
To paint a new complexion on an image, select "Duplicate Layer" from the Photoshop Layer menu. Find another image with the complexion you want and open that image in Photoshop. Use the Eyedropper Tool to select the color and then use the Paintbrush tool to paint that color over the skin you want to change. When you're done painting, change the Layer Style from "Normal" in the Layers Panel to "Soft Light" or "Overlay" to blend the skin tones. Reduce the opacity as needed by dragging the "Opacity" slider to the left. This technique can do wonders for adding a tan to a pale complexion or making a dark complexion lighter.
Image Adjustment Techniques
If you click "Adjustments" under the Photoshop Image menu, you'll find a few more handy tools for modifying skin tone. First create a duplicate layer of your photo and use a selection tool to select the skin. Then, use the Brightness/Contrast options to lighten or darken the skin. The Curves option can do the same thing for a more subtle effect. Drag the sliders in the Levels option or the Hue/Saturation option to make subtle changes to skin color. As with any of these options, the degree to which you drag the sliders depends on the photo and the effect you want. Remember to adjust the layer's opacity to blend the changes into the original layer so your image doesn't look overly "photoshopped."
Information in this article applies to Adobe Photoshop CC. It may vary slightly or significantly with other versions or products.