You need a black-and-white photograph.
If you have a color photograph, go to Convert to B&W.
There are presets for toning black-and-white photographs.
Go to the Presets panel on the left side of your screen in the Develop module.
You can add a faint coloration to a black-and-white photograph.
Even though this involves color, the term toning is used.
Typically, you add color only to the shadows, not to the midtones or highlights.
Split toning is where you add one color to the shadows, and add a second color to the highlights.
If you don't see the sliders, click the tiny black triangles in the panel.
Go to the Split Toning panel in the Develop module, and do the following.
1) Click the color box to the right of Shadows.
The Select a Color window appears.
2) Select a color.
If you haven't already, go to Select a Color Window.
4) You can further refine the hue and saturation with the Shadow sliders.
1) Do the above steps.
2) Repeat the above steps in the Highlights section.
3) Use the Balance slider to change the toning amounts in the highlights and shadows.
Try the following values for sepia tones.
You can use the values from the columns A, B, or C.
The column A color is what Photoshop Elements uses for its sepia color filter (Go to Filter > Adjustments > Photo Filter > Sepia).
* The HSL color model has three variables. You can only use hue and saturation in the Split Toning panel.
If you encounter a toning color that you like, but the values for it are not HSL, convert them with the HSL Color Picker by Brandon Mathis.
You can save your toning effect as a preset.
Do the following.
1) On the left side of your screen, click the plus icon at the top of the Presets panel.
The New Develop Preset window opens.
2) Enter a name for your preset.
By default, it will be saved to the User Presets section of the Presets panel.
3) Click Check None at the bottom of the window.
4) Select Split Toning in the middle of the window.
5) Click Create.
6) To use the preset, close and restart Lightroom.