Step 10
The next step is to create the illusion of light refraction and bend our background beneath the 'water' layer. To accomplish this we will need to make a copy of our 'background' Layer. You can do this by dragging the background into the 'New Layer' Icon at the bottom of the Layers Palette as in figure 23. Double click on the 'background copy' and rename it 'refraction'. Now we need something to bend it with. For this we are going to use the Displace Filter. But, before we can do that, we need to create something called a 'Displacement Map'.

Go back to the Channels Palette in your image and select the 'water 2' Channel. Select the entire channel (Select>All or Ctrl/Command+A) and copy the layer (Edit>Copy). Create a new document (File>New) and call it 'water displace. Accept all of the default values for the size, it should be exactly the same dimensions as the 'water 2' channel you copied. Paste the copy of the 'water 2' channel into this new document and flatten it (Layer>Flatten Image). Open the Gaussian Blur Filter and blur the image with a Radius of 6. Save this image on your hard drive as 'water displace.psd'.

Now for the Displace Filter. Close the displacement map you created and go back to your water image. Deselect (Select>Deselect or Ctrl/Command+D) and make 'refraction' the active layer. Open the Displace Filter (Filter>Distort>Displace) and set the Horizontal and Vertical Scale to 5% each. Set the Displacement Map: Stretch to Fit and the Undefined Areas: Repeat Edge Pixels as in figure 24. Click OK and you will be prompted to select a Photoshop file. Find the 'water displace.psd' you just created and click Open. Your 'refraction' layer should be 'pushed out' at you in the shape of your 'water' layer. For those of you that don't know what just happened, let me try to explain. Think about the displacement map you created as a three dimensional object for a moment. White areas represent high and black areas represent low. All other levels of gray represent varying levels of height based on weather they are darker (lower) or lighter (higher). Refer to figure 25. What we did was kind of push the 'water displacement map' through the 'refraction' layer from behind, wrapping the layer around the displacement image. The white areas pushed the image forward, while the black areas had no effect on the background at all. They remained flat. The only problem is that the background is 'bent' beyond the boundaries of our water object, which is why we made a copy of the background. Let's fix this. Once again, we need to load our 'water 2' channel and invert it. With the 'refraction' layer active, hit the Delete Key and problem solved! We have trimmed away the excess. The 'refraction' layer now blends beautifully with the 'background' layer below it.

We still have the problem with the 'water' layer being a bit on the light side, however. We will fix that by blending another version of the 'water' layer above the original 'water' layer with another Composite Mode. First, make a copy of the 'water' layer by dragging it into the New Layer Icon at the bottom of the Layers Palette like we did to copy the background layer. You should now have a 'background', 'refraction', 'water' and 'water copy' layers, in that order from bottom to top. Change the Composite Mode for the 'water copy' layer from Hard Light to Overlay. Merge the layer down by making 'water 2' the active layer and selecting (Layer>Merge Down or Ctrl/Command+E). Your image should now look like figure 26.

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Figure 23
Use the 'New Layer Icon' to create a duplicate of the 'background layer' by dragging the 'background layer' into it. This copy will be used to create the 'refraction' layer.

Displace

Figure 24
The settings for the Displacement Filter.

Water Displace.psd

Figure 25
The displacement map. White areas represent high, while dark areas represent low.

Water.psd (water)

Figure 26
The 'water' layer, 'refraction' layer and 'background' layer all working together to create the illusion of real water.