This is a really handy technique for making the lips stand out by shifting the shade of the lip color, brightening the natural highlights, and then lastly, doing a quick cleanup to give you really gorgeous lips.
Here’s the image we’re going to retouch by shifting the shade of the lips. If we wanted to change the entire color to something completely different, we’d probably reach for a Hue/Saturation adjustment layer, but in this case, we’re just going to shift the color that’s already there. My favorite option for doing this is Selective Color, so click on the Create New Adjustment Layer icon at the bottom of the Layers panel and choose Selective Color from the pop-up menu (as shown below).
When the Selective Color options appear in the Adjustments panel, by default the Reds are already selected, so all you have to do is move the top three sliders to push the lip color to a different shade (the fourth slider, Black, controls the lightness or darkness of the Reds). Let’s start out by clicking-and-dragging the Cyan slider almost all the way to the left (I dragged it to –95%), then let’s drag the Magenta slider almost all the way to the right (as shown below, where I dragged it to 86%). Of course, it doesn’t just change the shade of the lips, it shifts the red for the entire image, but don’t worry—we’ll fix that next.
Press Command-I (PC: Ctrl-I) to Invert the Selective Color adjustment layer’s layer mask, which hides the red color version behind a black mask (as seen below in the Layers panel). Now, with your Foreground color set to white, get the Brush tool (B), and choose a small, soft-edged brush set to 100% Opacity in the Options Bar. Then, carefully start painting over the lips (as shown here), and the new shade appears as you paint.
Continue painting until the lips are fully painted in, as seen below (this is a case where having a tablet and wireless pen really pays off, because painting in the lips like this with a pen takes all of 10 seconds).
If you want to shift the shade to something different, try dragging the Yellow slider to the left—I dragged it over to –55%. Look at the difference in the shade now.
If you want more of a red look to the lips, just increase the amounts of Cyan and Yellow by dragging them both way over to the right. Here, I dragged Yellow all the way over 100%, and then Cyan to 55% (I also increased Magenta a bit to 95%), and the lip color is really starting to look good.
If you want that deep, rich, ruby red lip look, here’s what to do: Start by returning all your Selective Color sliders to 0% (just choose Default from the Selective Color pop-up menu at the top of the panel), so they’re not having any effect at all, and the lips are back to how they looked when you first opened the image. Now, press-and-hold the Command (PC: Ctrl) key and click directly on the black layer mask thumbnail over in the Layers panel (as shown circled in red below). This puts a selection around the lips, made from the mask you painted earlier.
Now, click on the Create a New Layer icon at the bottom of the Layers panel to create a new blank layer, press D to set your Foreground color to black, and then press Option-Delete (PC: Alt-Backspace) to fill your lip selection with solid black. I know it looks bad at this point, but that’s all about to change. Go to the top of the Layers panel and change the layer blend mode from Normal to Soft Light and bam—the lips become that ruby red (as shown here). But, because your Selective Color adjustment layer is below it, you still have control (as you’ll see in the next step). Press Command-D (PC: Ctrl-D) to Deselect.
In the Layers panel, click on the Selective Color adjustment layer and then in the Adjustments panel, drag the Cyan slider back over to the left. Here, I dragged it over to –98%, and look how it shifts the shade once again.
That’s the end of the shade-shifting part, but if you’ve got spare time and really wanted to go in and take things a step further, I would start by brightening up the highlights on her lips. If you want a quick way to do it, just click on the Background layer in the Layers panel and press Command-J (PC: Ctrl-J) to duplicate it. Get the Dodge tool (O), and up in the Options Bar, set the Exposure to around 12% and make sure Highlights is selected in the Range pop-up menu. Then, with a small, soft-edged brush, paint a few strokes over all the bright highlight areas in the lips to make them even brighter (as seen here, where I’m painting over the highlight on her bottom lip). This makes a bigger difference than you might think.
If you have a few more minutes, you could clean up the inside and the outside of the lips a bit. If you’ve got lots of time, you could do add a skin softening technique. But, more likely, if you’ve got an extra five minutes or so, you’ll just want to get in there with the Healing Brush and Clone Stamp tool and remove all those little hairs under her lip and on the corner of her mouth. Do the inside of the lips with a very small Healing Brush (press Shift-J until you have it), and just Option-click (PC: Alt-click) to sample a nearby clean area and then click over little specks, spots, and anything that looks out of place. When you get to the little hairs under her lip, switch to the Clone Stamp tool (S), lower the brush Opacity to 35% in the Options Bar, choose a very small, soft-edged brush, zoom in tight, and then just Option-click to sample a clean area and clone those little hairs away (as shown here, where I’m cloning under her lip).