And that’s the result of two steps above. The difference may not be very noticeable but in my opinion subtle effects and details make a scene better.
To increase the contrast of the mountains and the sky add a Gradient Map adjustment layer and select the default Black to White Gradient.
Change the layer Blend mode to Soft Light and lower the Opacity to 60%.
In the layer mask use the Linear Gradient Tool to limit the effects of this layer to the upper part of the scene. Take a look at my layer mask below. Remember that in a layer mask white reveals and black conceals.
And here is how the image is looking now.
To shift the hue to a cooler blue add a Color Balance Adjustment layer and use the settings shown below.
Here is the effect of Color Balance Adjustment from above.
Add a Hue/Saturation adjustment layer and drag the saturation slider towards left to decrease the saturation.
Use the Linear Gradient Tool in the layer mask to limit this effect to the lower part of the scene (where the bottom of the sea it is supposed to be).
Below is the effect of the Hue/Saturation Adjustment layer we did in the steps above.
The surface of the sea seems a bit too dark and too blue and it doesn’t really match the underwater color. Let’s correct this by adding a Color Balance Adjustment layer .
Paint with a round soft white brush tool in the layer mask to apply this effect only to the surface of the water. By now you should appreciate the effects of selective masking and be quite familiar with the use of layer masks. That’s a good thing because layer masks are invaluable to a non-destructive editing technique.
And here’s the result of our Color Balance adjustments.
The image look very nice and unified but I decided to add a little hue contrast by making the scene above water more orange. Orange is the opposite of blue on the color wheel so we will have a nice contrast and some beautiful colors. Add a Color Balance Adjustment layer with the settingsh shown below.
In the layer mask use the Linear Gradient Tool to limit the effect only to the upper part of the scene. This is how my layer mask looks.
And this is how the scene looks now. One more step and we are done.
As a final adjustment I decided to make the underwater color a little more cyan and intense so I added another Color Balance Adjustment Layer.
…using the Linear Gradient Tool and the layer mask I limited the effect only to the lower part of the scene.
And this is where I decided to step with my adjustments. Off course you can continue to add little details and elements to improve your image but in my case I consider the scene looks complete.