Now that we have our layer with the cool and dark colors defined, we can blend the layer into the image and adjust the results.
To blend the layer into the image, simply change the blending mode of the top layer to Soft Light.

We'll be using the Levels tool to adjust the effect. Open the Levels tool (Image> Adjustments> Levels or Ctrl+L). To increase the effect, move the black and white input sliders towards the center.

Now that we're done editing, change the image mode back to RGB color (Image> Mode> RGB Color).

This effect may cause some skin tones to be over saturated. To fix this, simply using the Hue/Saturation tool (Image> Adjustments> Hue/Saturation or Ctrl+U) and lower the saturation.

Rollover the image below to see the before and after effect.
