Aerial and Atmospheric Perspective
To create the impression of depth in your drawing or painting one of the techniques you need to utilise is atmospheric perspective, also known as aerial perspective. Atmospheric perspective results in objects further away from the viewer getting lighter in tone, bluer in color, more dull (colors less pure) and softer edged. The effect is due to the atmosphere between you and the object you are looking at.
Now if you are just drawing and painting with a single colored ink, most often black, then you can’t use color changes but you can still utilise tones and edges to create a feeling of depth in your work through atmospheric perspective.
To create a lighter tone with black ink you have to add water to it. When I am painting something that is to appear in the distance I find it easier to add some water to a little ink before I mark the paper. I then paint the distant objects with this lighter toned ink and water mixture. If you start drawing with your darkest ink and then add water to the paper to lighten it you may have to work harder to get the right tone than you need to. If you mix your lighter tone first you can test it on a scrap piece of paper and when it is right you can confidently draw or paint in your distance area in your landscape or artwork.
Then as you move closer towards the foreground in your drawing you can add more ink to your original mixture until you are painting with pure ink for your darkest tones.
Softer edges are creating by lightly drawing with your pen or painting with your brush into already wet areas or your work. Remember to use lighter toned mixes of ink and water when creating soft edges in the distance.