Volume, shadows, depth, modules, details, blurring and an image composition.
Composition – Shadows create volume
Shadows are important and space creating. Sometimes shadows can explain volumes much better than the object itself. A flat circle becomes a ball through the appearance of a shadow. Example: Edgar Degas (1834-1917)
Modules create space
Modules with a similar shape, but in different sizes, create space. Three or more creates a stronger effect than two. Example: Francesco Guardi (1712-1793).
Repoussoir (from French = pull back), is the secret of all postcard photographers to create a depth in the images. To create this depth you position an object in the foreground of the image. Example: Caspar David Friedrich (1774-1840)
Details – blurring
Details are brought forward in an image and blurring is pushed to the horizon. This is how we see things with our eyes and can be used to create space. Example: Turner (1775–1851)
Atmospheric perspective. Lighter towards the horizon
Air perspective. Lighter colours are perceived as further away. Example: J. M. W. Turner (1775-1851)
Saturated colours appear closer
Saturated colours appear closer than unsaturated colours. Example: Lars Hertervig (1830-1902)