The Black & White adjustment layer can be used to tint images, but also colorise
To do this, apply the adjustment as a new layer from the Layer menu, and change its blend mode to Hue.
Tick the Tint box in the adjustment and click on the small colour swatch to set the hue.
You can see just how this detailed image was originally created, among other expert techniques, in our Dramatic Photo Effects Feature in issue 103, on sale now from Imagine Shop and GreatDigitalMags.