EXPERIMENT WITH GRADIENT MAPS
Use this alternative approach for tonally targeted colouring effects
Gradient Maps are another powerful colour adjustment tool. They allow colour to be selectively applied to an image depending on brightness values, so that differential toning can be added to highlights and shadows. Set contrasting hues for the Foreground and Background colours, then choose the Gradient Map from the Adjustment Layer palette. Click on the gradient and move the Highlight and Shadow Stops to alter where toning is applied. Change the layer blend mode to Soft Light or Overlay.