Landscape sketching is a great way to begin working directly from the landscape. It will help you to understand general principle about landscapes before attempting to work in paint (which can be a bit daunting!).

This lesson will introduce two key principle which will help you to make sense of and arrange the shapes and values in the landscape. I won’t go into technique too much, we will cover this later. For the time being, I want you to gain an understanding of these two important concepts.

Carlsen’s Theory of Angles

One of the most useful resources for landscape painting (and drawing) was written in the early 20th C. by an American painter – John F. Carlsen. It’s called ‘Carlsen’s Guide to Landscape Painting’.

One of the most useful principles in the book is his Theory of Angles which is used to group features of the landscape into value masses based on their relation to the sun. As we have seen in previous lessons, planes that face towards the light source will always be relatively lighter than planes which face away from the light source.

As the source of light in a landscape is the sun, all features of the landscape are brighter or darker depending on how much of their surface faces towards the sun.


These are the four value groups that are used in the theory of angles:



The value of the sky can vary depending on the position of the sun and the amount of cloud cover but is almost always the brightest value mass in the image as it is the source of light. Somewhat counter-intuitively, the value of the sky is usually slightly darker on clear day and brighter on overcast days. This is because light rays travelling through a cloud bounce around within the cloud before eventually hitting the ground, whereas they fall directly on the ground on a clear day. Light refracting within the cloud illuminates it, and also reduces the amount light reaching the ground. This phenomenon means that the sky can look almost pure white on an overcast day, whereas it is a slightly darker value (and more blue) on a clear day.

To help understand this concept better, find a frosted pane of glass and compare it to a clear pane of glass. The frosted glass looks brighter because the light bounces around within the glass before carrying on its way.



Flat (or reasonably flat) sections of the ground tend to face directly upwards, which means that they receive a lot of direct light from the sky and are generally brighter than other features of the landscape.


Upright Objects (Trees, walls, people etc.)

Upright (or near vertical) objects only catch slanting light rays so the will tend to be the darkest parts of a landscapes (excluding shadows of course).


Angled Surfaces (Mountains, top of buildings etc.)

Angled surfaces include mountains/hills, rocky outcrops and manmade structures (roofs of building are often slanted. These will vary in value depending on their angle – the nearer horizontal they are, the lighter they will be.


These general principles are of course quite variable, obvious exceptions include:

  • A setting sun is so low that vertical objects will receive more light than the ground plane.
  • On a stormy day the darkest parts of cloud will be darker than other parts of the landscape.
  • Local value is important – the white walls of a house will be lighter than green grass on the ground, despite receiving less light than the grass.


However, being aware of the overall concept will help you to mass parts of the landscape when sketching. This will help you to arrange the scene more simply and confidently before adding detail.

Aerial Perspective

Aerial perspective is a bit more straightforward than the theory of angles, and tends to be a pretty consistent rule. As we look further into the distant part of a landscape the lighter it becomes. So the darkest values will always occur in the nearest part of the foreground. This is because of particles in the atmosphere which are not visible to the naked eye. While we can’t see the particles they bounce light which makes them glow a little. The further into the distance we look, the more of these tiny glowing particles we look through, resulting in a veil of illuminated atmosphere increasing into the distance. As a result, the further into the distance we look, the lighter things get.