Play with atmosphere & depth of field in an underwater scene with Photoshop
Creating a sense of depth is one of the key ingredients when rendering a close up underwater scene. Two elements will help you to achieve this: the depth of field, and the atmospheric perspective. In this tutorial you will learn how to render a fish in front of a simple background and then use a hand painted depth channel in order to add depth of field and atmospheric perspective.
Creating a drawing
There are many approaches to start a painting and my favorite one is to create a neat line drawing. Not only does it make your process easier, it also can be used as a piece of art on its own. Don‘t forget to include background elements, such as anemone tentacles, corals, or rocks. We will need them later to demonstrate our depth of field effect.
Creating layer masks and choosing colors
Once you are happy with our drawing it‘s time to create our mask layers. Create layers for each element and lock their transparency or, if you would like to render my version of this exercise, feel free to use the layers from the accompanying PSD. Once you are done, choose the colors for your painting and fill the layered elements accordingly. Try a few variations and place them next to each other in order to find the most successful one. I recommend you use a separate layer for each color of the fish‘s pattern as well. This will make things much easier later on.
This step is fairly straight forward. Because we are going to look at the atmospheric perspective in a later step we don‘t have to worry about it now. Ctrl-click the according transparency layer and paint your shadows onto a separate layer. I usually group my layers so I have all shadow layers in one group. I used a dark blue for the shadows of the background and set it to 50% opacity. For the fish I chose a dark red with the intention to make it look more radiant. You can pick the colors from the reference image or choose your own.
This step is very similar to step 3, we Ctrl-click our layers in order to get our selection, create a new one for each element, but this time we set our layers to screen. Use a warm yellow for the fish to make it‘s scale shine and something slightly cooler for the rest, depending on the mood you chose. Repeat this step for a second light in order to create a more dramatic scene.
You followed the steps along and now most of all colors you will need are already on the canvas. Use your color picker and your favorite brushes to shift them around in order to add your detail and give your image a nice hand painted feel. Use a color dodge layer to give your highlights an extra boost.
Creating a Depth Map
You still remember the locked layers we used in order to get our selection masks? Good, because we are going to need them once again. This time you need to them to create the depth map by painting white what at the very front and filling black what is at the very back. Make sure to create a nice gradient in order to get the best result from this. Side note: Keep this image as an extra file if you would like to create a Facebook 3D photo from your end result.
Copy your depth map and hide one of them for later uses. Then take the one that is left and set it to multiply. Create another layer, turn it into a clipping mask, set it to screen, and fill it. I went for a pink because it seemed to go well with the established atmosphere, but feel free to experiment. Then I created a layer mask for the depth channel layer and smoothly erased the areas where I did not like the effect.
Depth of field
Now copy-merge your whole image. Turn on the backup of the depth map and make sure it is at the very front. Switch from layers to channels in the sidebar and ctrl-click any of the 4 channels you will find. Then go back to your layers tab and select the layer with your merged image. Create a layer mask from the selection and disable it. Then go to your filters and choose Lens Blur. The layer mask should be set as a source by default. Adjust the radius and the focal distance until your result looks satisfying.
You made it this far, congratulations! You followed through this tutorial and created your own underwater scene. Add a few particles, some extra bubbles or whatever you think is missing in order to give your painting a final touch-up. I went with some corals in the background and some sun beams coming from the surface above.