It is going to be an easy-to-follow photo colorizing tutorial. It is useful for web, poster, wallpaper and cover design.
Ingredients:
- Desaturation
- Layers
- Gradients
- Blending
Difficulty: Easy
Preview 
Here is our original image.
Open the image in Adobe Photoshop.
Desaturating the image
Create a new adjustment layer. At the bottom of the Layers window, click the Create a new fill or adjustment layer icon (the 4th icon in the row). If you cannot see the Layers window, make sure the Layers option is select in the Window menu at the top. Hovering over the icon shows a hint.
In the Hue/Saturation popup window, drag the Saturation slider to –70. The Preview check box allows you to see the changes—try to clear it and then select it again.
You see colors have faded in the image. Here is what we get.
Colorizing the image
Create a new layer (at the bottom of the Layers window, click the Create a New Layer icon (the 6th icon in the row).
Set the blending mode to Soft Light (select Soft Light from the drop-down menu at the top of the Layers window).
Select the Gradient tool and fill your layer with a gradient of your choice.
Variations of the colorizing technique
Download the PSD file (766 KB).
I hope you enjoyed this tutorial.