The Split Toning tool allows you to add a color tint to the highlights and shadows of your images. Why would you want to do that to a black and white image? Well, some of the magic in black and white printing is that black and white prints aren't always perfectly neutral. In fact, as photographers who have worked in the chemical darkroom know, there various black and white paper emulsions produce a range of tones that give prints a warm or cool look. Part of the skill that goes into making a great print is choosing the right paper to give the finished print the right tone.

Let me show you an example. Here's the before and after views of one of the images I took a few weeks ago in Wiesbaden, Germany. It's an image of one of the fountains in front of Das Kurhaus. It's an image that I didn't like so much in color because of the various temperatures of light in the scene, but really liked in black and white.

What's not obvious at first glance is that the image on the right isn't a purely neutral image. In fact, I've used split toning to cool the shadows and warm the highlights. To show you the effect of the tool, here's a movie that you scan scrub back and forth through and see the effect of the Split Toning tool.

Here's the final settings for the Split Toning control that I used for the image:

Now that you can see how it's done, you can view the result in a larger size on Flickr.