Aerial perspective refers to distance. When looking at an image, how does the viewer get a sense of depth? The artist can add depth to an image using various tricks.
There are various ways of depicting aerial perspective.
Change the colour
Background scenery such as distant mountains tend to look more blue.
Buildings can be blued out:
People can also be blued out:
Or a blue outline may suffice.
Whereas aerial perspective is more noticeable across vistas covering large distances, artists can also use it to create depth in very intimate settings, for instance when foreshortening:
At sunset, or in the city, the blue is often swapped out for orange hues:
Warms in the background, blues in the foreground definitely convey the feeling of a place cooling down after a hot day.
But not always. I feel the image below aims to convey atmosphere rather than time of day.
The general rule of cools in the background, warms in the foreground can also be inverted for a surreal, pop-art kind of look.
In a utopian setting where you don’t want any desaturation, you can change the palette. Often it will be cool colours for the background palette, warm for the foreground, but the cools are as bright as the warms.
The further away, the less vivid the colours. Or even if there are no colours at all, the background will seem more see-through. In digital illustration, this can be achieved by lowering the opacity of the background images.
Fantasy illustrators tend to make heavy use of this technique as it creates a highly atmospheric image — often dystopian.
Make use of blur
Background scenery might be more blurry if you want to draw attention to your foreground image. This is a natural consequence of taking a photograph using an SLR camera and can also be applied to art. (It’s also a natural consequence of being short-sighted…)
Or, you might blur out the foreground and leave the background layer in focus.
Frame With Very Dark Foreground
In this image of Beauty and the Beast’s castle, artist Petur Antonsson has used four distinct perspective layers, starting with almost black in the foreground, brightest for the focal point (the house), an ochre layer of trees and a misty, blue castle behind.
Darken foreground lines
Change the amount of detail
Use white lines as background scenery
Use unfilled objects (with dark lines) as background scenery
In Drahos Zac’s illustrations for The Pied Piper, there may be ominous reasons for avoiding the sepia fill on background buildings: The inhabitants of those particular buildings may have already died. This theory holds up when you consider some of the foreground characters are also left unfilled. This feels reminiscent of ghosts.
Silhouettes As Background Objects
Or the silhouette might have a bit of detail. You can be as silhouette-y as you like.
Silhouettes don’t have to be relegated to the background, as proven by this photograph: