Step 5

Create a new Curves Adjustment Layer by going to Layer > New Adjustment Layer > Curves. Use the settings shown below to darken and increase contrast and then clip the Curves Adjustment Layer to the underwater layer by Alt-clicking between the two in the layer palette.
Clipping a layer means that the upper layer will show only through the visible pixels of the bottom layer thus leaving the rest of the scene unaffected – in our case the darkening effect of the Curves Adjustment Layer will be applied only to the underwater layer.

Step 6

Now let’s change the color of the underwater layer so that it will match the rest of the scene. Create a new Color Balance Adjustment Layer by going to Layer > New Adjustment Layer > Color Balance and using the settings shown below. Clip this layer to the underwater layer by Alt-clicking between the Color Balance layer and the Curves layer. You can have multiple clipped layers – layers that will show only through the bottom layer.
You can find all the adjustments layer used in this tutorial under Layer > New Adjustment Layer > … so from now on I will simply just say the name of the needed adjustment layer – you know where to find it.

Step 7

Let’s add some darkness to the water. Create a new layer (Ctrl + Shift + Alt + N) and set the blending mode to Overlay. Choose the standard round soft brush (B) and set the opacity to 30%. Paint with black on the lower section of the underwater. If the effect is not strong enough repeat this step with another layer set to Overlay – you can fine tune the final result by lowering the Opacity of the duplicated layer.

Step 8

Let’s add some lightness to the upper region of the underwater layer. Create a new layer, set the blending mode to Overlay and paint with a round soft brush with white over the upper section of the underwater.

Step 9

Let’s add a center source of light. Create a new layer and set the foreground color to #c4ec9e. With the round soft brush at 70% Opacity click a couple of times in the center of the scene to achieve the result shown below.