Open the file “Underwater1”. Select all and copy/paste in our document. Convert the layer into a smart object and place the underwater as shown below.
Click on the underwater layer in the layer palette and press Ctrl + G to add it to a group. Add a layer mask to the group (Layer > Layer Mask > Hide All) and use the Pen Tool to create a path as indicated in the layer below. Press Ctrl + Enter to convert the path into a selection.
Press D to set the colors to default and while in the layer mask of the group press Alt + Backspace to fill the selection with white and thus reveal the underwater inside the selection. Press Ctrl + D to deselect.
Open the file “Underwater2”. Select all and copy paste into our underwater group. Change the blending mode to Soft Light.
Open the file “Bubbles”. Select all and copy/paste in our underwater group. Change the blending mode to Overlay.
Create a new Hue/Saturation Adjustment Layer and place it inside the underwater group. Change the Hue to -22 to change the hue of the water to a more pleasant one.
Open the file “Water Surface”. Select all and copy paste in our scene. Desaturate the layer (Image > Adjustments > Desaturate) and convert it to a smart object. Place the water surface as shown below.
Click on the surface layer in the layer palette and press Ctrl + G to add it to a group. Add a layer mask to the group and using the same techniques we used at steps 27 and 28 to reveal the surface only where it should be as shown below. Name the group Surface.
Create a new layer and place it inside the Surface group. Set a nice blue as foreground color (#468ff2) and press Alt + Backspace to fill the layer with that color. Change the blending mode of the layer to Color.
Create a Hue/Saturation Adjustment Layer and place it inside the Surface layer. Change the hue to -14.
Create a new layer and change the blending mode to Overlay. With the standard round soft brush at 10% Opacity paint some white shading in the middle of the surface.
Use the Pen Tool to create a selection as shown below. Create a new layer (or more) and change their blending modes to Overlay for lighten effects and Multiply for darkening effects. Paint with the round soft brush very subtly with white in the center of the selection and with black on the margins of the selection.
Do the same thing for the left side of the water. As you can see I am using multiple layers for flexibility.
Create a new layer and draw a vertical line right over the corner of the water with the standard chalk brush (2px size). Lower the opacity to 49%. As you remember from previous steps you can either click on the start point with chalk brush and Shift-click on the end point of the desired line.
Create a new layer and with the round soft brush paint with a dark blue some squiggly lines where the water waves meet the underwater texture to create some dynamism. After that paint other squiggly lines over the blue ones but this time use white.
Now it’s time to populate the underwater with some objects. Open the “Plant” file and copy all. Go back to our document and paste. Convert the layer into a smart object and place it somewhere on the bottom of the water. Lower the opacity to 5%. Do the same for all the following objects by opening these various files: Fish, Diver, Shark. Vary the opacities between 10% and 20%.