This tutorial is written for PhotoShop CS3, but can be recreated in other versions.

In this tutorial, you will learn how to create an underwater scene from scratch.

We will start with a blank canvas of 400×600 pixels. Then we will add a linear gradient like so:

Then we’ll want to add a new layer and create a lightened area for the sea bed. This will be where the sun shines through the top and lights up the floor. You should use a soft brush for this:

Next, make a selection about three quarters the size of the canvas, like so:

Now in a new layer with default colors (press D), goto Filter > Render > Clouds. It might take a few goes to get what you’re looking for because clouds are generated at random, but you’ll have something like this:

Goto Edit > Transform > Scale and expend the clouds out to fill the canvas. Then goto Filter > Artistic > Plastic Wrap. For Highlight Strength, choose a value between 10 and 15, Detail between 1 and 5, and Smoothness between 10 and 15. We should end up with something like this:

Goto Edit > Transform > Distort and resize it to fit at the top, like so:

Next, with the clouds still selected, goto Filters > Render > Lighting Effect. We will choose Omni, and play around with the settings until you find a light you like. We are trying to recreate the sun shining through the surface of the water.

Next, take a soft brush and erase around the bottom of the layer we just created, and follow the light curve, like so:

Now we change the Blend Mode of this layer to Linear Dodge, and reduce the Fill to between 50 and 60%. We should have this:

Now to do the bottom. Duplicate the layer we just created for the surface water, and Edit > Transform > Flip Vertical. Then move it down to the bottom and change its Blend Mode to Color Dodge and the Fill to between 30 and 40%. You should now have something that looks like this:

As a finishing touch, we can add a beam of light being shone through the water from the sun. In another new layer, choose a brush that’s almost the size of the width of the canvas and paint a lighter color down the middle, like so: