There are many ways of achieving this in Photoshop, but this is my favorite.  It adds color without being overly harsh, and you can be very selective about the colors that get enhanced.  Anyone can jack up the saturation sliders, but this is a controlled, localized way to achieve that effect.  This is a trick I learned a year or so ago from Smashing Magazine.  If you’ve never heard of them, they are a great source of information for photographers and designers, so do yourself a favor and check them out.  I’ve been using this technique to add color and brightness to parts of my images that could use a little more “oomph”, especially to HDRs.  The HDR post processing tends to produce a flat result, and I find that even after some levels/curves adjustment in Photoshop there are some areas of the image that need more contrast and color.  Anyone with competent PS skills can pull this off, and I’ll show you how!  Let’s get started.

I’m going to use my photo “Back from Brooklyn” as the example in this tutorial.  As you can see from the photo below, it’s very flat looking, even though I’ve run it through Photomatix and Perfect Photo Suite already.

It’s quite dull, especially the sky.  Most of my HDRs are this way.  Yes, you can increase the color saturation in Photomatix, but I prefer to not to push it too much and control color saturation in Lightroom, Photoshop, and OnOne Perfect Photo Suite.  This method gives you precise control over the colors, effectively letting you control the mood of the whole photograph.

1. Unlock the background layer and make a new layer. Name it whatever you like, I use Enhanced Color a lot for these.

2. Change the blending mode of the new layer to “Color Dodge” and set the opacity to 15%.  This is a starting point.  The opacity can be changed later to lighten/enhance the color even more.  Play around with the opacity slider after you’ve painted in the color until you feel that it’s right.  Color Dodge is going to not only enhance the color, but the brightness as well, since it’s “dodging” out some of the exposure and lightening the area.

3. Use the eyedropper tool (I) to select the color you wish to enhance.  In this case, I started with the sky because it’s just too dull. I selected a nice blue and started painting with the brush (B) tool. You can also supercharge the color by using the color picker to select a deep, vibrant color of the same shade. This really adds some saturation.  I did not do this on this particular image, but I have in the past with good results.  After painting the sky, it now looks like this.

4. Repeat the color selection process for every hue that you want to add brightness and saturation to.  This can get very involved, as it did in my example image, but the end result is well worth your time.  This is the result of using this process to enhance the color in this image.

That’s it!  The whole process is very simple, but knowing the correct settings is the key to not oversaturating the image.  New layer, color dodge, 15%, sample your color, paint, tweak.  That’s our mantra here.  You can certainly tinker with the settings to your own taste, and I advise that, but this is a good starting point I’ve found that consistently works for me.  This adds depth and character to the image, and I do this on nearly all of my images as a finishing touch.  It’s a very subtle and careful method to enhancing the color saturation of your images.  I hope you all enjoyed this tutorial, and if you have any questions, please feel free to comment and I’ll answer as best I can.  Thanks for reading!