We all want our eyes to look as vibrant as they can in photos, but sometimes the camera just can't capture all the details in the human eye. Well here's how you can bring out the details via photoshop and then some. :)
There are many methods to do this, and some look better than others. This particular method is the more natural way to add color and contrast without appearing unrealistic or "photoshopped."
Step 1: Basic Retouching
I like to start by adding contrast to the whole eye. Make a new layer, (this allows you to work on the layer rather than the original image so if you need to go back and change something, you can do so without having to start all over), and use the dodge and burn tools from your tool palette to darken the eyelashes and lighten the whites and highlights in the eye. It works best if you have your dodge and burn settings, (at the top of your toolbar), on midtones at about 10-15% opacity.
Step 2: Selecting the Iris
Now you can make a selection of the iris using the slection tool of your choice. Since this is not a particularly detailed selection, I simply used the quick selection tool. I felt that her eye would look a little more interesting if we added some green detail to it, so within our selection, I'm going to add some color detail.
Step 3: Adding Color
We don't want her eye to look unrealistic, so when we add color detail, we mean just that. I will not be fully changing the color of her eye, but adding a little green to the inner part of the iris and blending it with her original eye color.
Using the brush tool, I'm going to set the opacity on 15% and put it on a color blend mode. This will allow me to paint the color into her eye without painting out the details. Using outward brush strokes, paint around the pupil to give it and uneven coloring that follows the natural lines in her eye.
Step 4: Preparing to Add Contrast
Now that we have a nicely painted eye, though a little messy, (we'll fix that later), we can concentrate on adding some more contrast. For this, we need to feather our original selection. Go to select > modify > feather and feather the selection to about 3-5 pixels. This fades the outer edge of our selection so that it doesn't look like a crisp line when we add contrast.
Step 5: Adding Contrast
Now that we have our selection feathered, we can add contrast using a curves adjustment layer. This is done by personal preference, so whatever you think looks the best, I say go for it! In this example, I didn't feel that much contrast was really needed and only added a little.
Step 6: Final Touches
After adding contrast, I felt needed to go back in and blend the color and define the pupil a little more. In order to go back to working on the iris instead of the curves adjustment layer, you can either select the original layer you made, or make a new one, which is what I decided to do.
In order to blend the colors in a bit better, I went back to my color picker, (still using the brush on 15% and the color blend mode), and add more brown to the outside edges and a little bit into the green.
After blending the color, I added my final touches by dodging and burning parts in the iris, (remember, be sure to have your brush set to midtones with an opacity of 10-15%), such as some of the darker spots and details and the outer rim.
As I said before, there are many ways to do this, and each method has it's benefits. The results of this method may vary depending on the original photo and eye color of course, but I feel it is a simple proccess that works well.
If you're looking to make your eye pop even more, Here's an instructable on adding more "life" to eyes. :)