What I’ll show you first is one way to enhance the existing eye character in a photo.
Take a look at Figure 2.1. This is the image eye.jpg from this book’s source files; it should
be open in Photoshop as you begin. The enhancement you’ll add here is to make this mixed
color richer and brighter. To do that, you’ll use duplicated layers, layer masks, and a couple
of blending modes. Duplicate the Background layer and change the blending mode of the new layer to Overlay. Note that the entire image becomes a bit darker as the new layer blends with the background. This does help enhance the color of the eye, but the skin around the eye
becomes darker also. A mask will alleviate this problem quite nicely.
At the bottom of the Layers panel, click the Add Layer Mask icon. By default the mask is filled with white, allowing the contents of the entire layer to be seen. You do not want all of the pixels to be seen, however; just those of the iris and pupil. With the layer mask selected, choose Edit → Fill and fill the mask with black set to 100% opacity and Blending Mode set to Normal. Figure 2.2 shows the Layers panel at this point in the process. Set white as the foreground color. Select the Brush tool, and with a softedged round brush, paint over the iris and pupil. Adjust the brush size accordingly so that you are painting only within the diameter of the iris. Although it’s not necessary to have a steady hand, you may want to create a selection of the area. In this instance the Elliptical Marquee tool will work just fine, because the area being enhanced is round. As you paint, the pixels on this layer will be revealed. The layer is still set to Overlay, so the color of the blended layers
comes through (see Figure 2.3).
To brighten the eye a bit (the goal is to brighten the colors without darkening the eye),create a new layer above the Background Copy layer and set the blending mode to Soft Light. With the foreground color still set to white, paint over the iris in this layer also. The change is subtle yet effective. Figures 2.4 and 2.5 show before and after shots. See the difference?