A duotone is a picture in two tones or colors. We’re going to make an easy duotone by first converting the image to black and white, and then changing the tone of the shadows.

Here is our original image:

First, we’ll convert it to Black and White

Move into the Develop module (keyboard shortcut “D”) and clicking “B&W” in the HSL / Color / B&W panel (I’m using the Lightroom 3 Beta; in Lightroom 2, click “Grayscale” in the HSL / Color / Grayscale panel):

Now the image looks like this:

Next we’ll go to the Split Toning Panel

Move the Saturation slider under “Shadows” to 25. As you can see, our image now has a red tone:

Next we’ll adjust the hue slider under “Shadows.”

Orangey-yellow tones look nice, but it’s a matter of preference that may also depend on the image you’re editing. Just ignore the “Highlights” slider.

After tweaking the exposure and adding a vignette, here is our final image:

This striking but simple duotone method is courtesy of Scott Kelby’s Lightroom Killer Tips class at Photoshop World in March 2010.