Using Photoshop layers and simple blurring effect to create ‘depth of field’ in your illustrations.
This is a technique that can be used to enhanced ZBrush renders and add atmosphere.
The key to making this fake DOF look good, is basically to paint every element in separate layers. This first image below is just a quick sketch nothing too detailed, but you can get a sense of the colour palette and composition.
The next step is to add some details (I use various references of specific trees and branches with snow). but again just blocking out some colours and tones always working from background to foreground.
The important thing to remember is that every new element that you add, should be in its own layer. At this point I’m only creating the background, so you can see how I even painted over the tree on the left-hand side. This tree is closer to the camera and it should be on its own layer anyway.
For every new element, create a new layer in photoshop. The shapes don’t have to be very detailed as long as they communicate the form. Concentrate on adding subtle colour variations and make sure that the silhouettes are interesting.
Keep in mind that probably not all the environment is going to be blurred. There might be elements in the composition that will be closer to the focal point (which should be sharp). In this case, the tree on the right is relatively close to the character that I want as the centre of attention, so I detailed a bit more than the rest.
I also added some branches and some ‘blobs’ of colour on the left to add contrast and create some visual lines to guide the viewer towards the centre where the character will be.
If you look at references, sometimes very bright points in the foreground or in the background, are very localised and when blurred, they produce the rather distinct circular shape. Using the lens blur filter in Photoshop, you can get a similar effect, but it could be quite slow. so for things like the yellow bright branches on the left I painted them with the shape I wanted the blur to look like.
Using a hard brush with opacity you can paint the main structure of the branches and then, to create the ‘bright circles’ of colour, use single clicks with different pressure over the path you made.
At this point, I also added a layer of snow particles that will sit in the distance.
Now that you have all the elements of the environment in place, you can place your character in the scene and stat blurring the layers at different values to create the effect.
Since every element of the composition is separated in different layers, we can select them individually and apply a blurring effect:
Select the desired layer and go to Filter > Blur > Gaussian Blur. From the pop-up window enter a value for the ‘Radius’ and click OK.
Here is an example of how I used the Gaussian blur on the layers (the amount will vary depending on the size of the document since is calculated by pixels, so the more image resolution you have, the bigger the values you’ll need to enter):
I added a few more trees in the foreground and used the same technique to blur them out.
Here is another illustration of the same character with a different mood, but following the technique esplained on this post.